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India GST Return (GSTR-3B / GSTR-1)

Prepare, review, classify, or advise on India's Goods and Services Tax (GST) for a self-employed individual, freelancer, or small business.

IndiaTax year 2025· Last reviewed Apr 13, 2026

Key facts — India, 2025

FieldValue
CountryIndia (Republic of India)
Tax structureDual GST: CGST + SGST/UTGST (intra-state) or IGST (inter-state)
Standard rate18% (CGST 9% + SGST 9% / IGST 18%)
Lower rate5% (CGST 2.5% + SGST 2.5% / IGST 5%)
Demerit rate40% (CGST 20% + SGST 20% / IGST 40%) -- luxury/sin goods only
Nil/exempt0% -- fresh food, healthcare, education
Zero-rated0% -- exports, SEZ supplies (with ITC refund)
Key ruleIGST rate = CGST rate + SGST rate, always
Primary return formsGSTR-3B (summary + tax payment); GSTR-1 (outward supply details)
Filing portalhttps://gst.gov.in (GST Common Portal)
AuthorityCentral Board of Indirect Taxes and Customs (CBIC)
CurrencyINR only
Filing frequenciesMonthly (turnover > INR 5 crore); Quarterly under QRMP (turnover <= INR 5 crore)
GSTR-3B deadline20th of following month (monthly); 22nd-24th of month after quarter (quarterly, by state)
GSTR-1 deadline11th of following month (monthly); 13th of month after quarter (quarterly)
Registration threshold (goods, general)INR 40 lakh aggregate turnover
Registration threshold (goods, special states)INR 20 lakh
Registration threshold (services, all)INR 20 lakh (INR 10 lakh special states)
E-invoicing thresholdINR 5 crore aggregate turnover (any FY from 2017-18)
E-way bill thresholdINR 50,000 consignment value
GSTIN format15-digit: 2 state code + 10 PAN + entity code + Z + checksum
ContributorOpen Accounting Skills Project
Validated byDeep research verification, April 2026
Validation dateApril 2026

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About

Use this skill whenever asked to prepare, review, classify, or advise on India's Goods and Services Tax (GST) for a self-employed individual, freelancer, or small business. Trigger on phrases like "GST return", "GSTR-1", "GSTR-3B", "GSTR-9", "file GST", "GST classification", "HSN code", "SAC code", "input tax credit", "ITC", "reverse charge", "e-invoicing", "e-way bill", "CGST", "SGST", "IGST", "inter-state supply", "intra-state supply", "place of supply", or any request involving Indian indirect tax compliance. This skill covers regular (non-composition) GST-registered taxpayers with a single state GSTIN only. Composition scheme, multi-state, SEZ, e-commerce operator, and ISD registrations are in the refusal catalogue. ALWAYS read this skill before touching any India GST work.

IndiaTax year 2025

Full guide

India GST Return Skill (GSTR-3B / GSTR-1) v2.0

Section 1 -- Quick reference

Read this whole section before classifying anything.

FieldValue
CountryIndia (Republic of India)
Tax structureDual GST: CGST + SGST/UTGST (intra-state) or IGST (inter-state)
Standard rate18% (CGST 9% + SGST 9% / IGST 18%)
Lower rate5% (CGST 2.5% + SGST 2.5% / IGST 5%)
Demerit rate40% (CGST 20% + SGST 20% / IGST 40%) -- luxury/sin goods only
Nil/exempt0% -- fresh food, healthcare, education
Zero-rated0% -- exports, SEZ supplies (with ITC refund)
Key ruleIGST rate = CGST rate + SGST rate, always
Primary return formsGSTR-3B (summary + tax payment); GSTR-1 (outward supply details)
Filing portalhttps://gst.gov.in (GST Common Portal)
AuthorityCentral Board of Indirect Taxes and Customs (CBIC)
CurrencyINR only
Filing frequenciesMonthly (turnover > INR 5 crore); Quarterly under QRMP (turnover <= INR 5 crore)
GSTR-3B deadline20th of following month (monthly); 22nd-24th of month after quarter (quarterly, by state)
GSTR-1 deadline11th of following month (monthly); 13th of month after quarter (quarterly)
Registration threshold (goods, general)INR 40 lakh aggregate turnover
Registration threshold (goods, special states)INR 20 lakh
Registration threshold (services, all)INR 20 lakh (INR 10 lakh special states)
E-invoicing thresholdINR 5 crore aggregate turnover (any FY from 2017-18)
E-way bill thresholdINR 50,000 consignment value
GSTIN format15-digit: 2 state code + 10 PAN + entity code + Z + checksum
ContributorOpen Accounting Skills Project
Validated byDeep research verification, April 2026
Validation dateApril 2026

Key GSTR-3B tables (the tables you will use most):

TableMeaning
3.1(a)Outward taxable supplies (other than zero-rated, nil-rated, exempted) -- all taxable sales + tax collected
3.1(b)Outward taxable supplies (zero-rated) -- exports + SEZ supplies
3.1(c)Other outward supplies (nil-rated, exempted)
3.1(d)Inward supplies (liable to reverse charge) -- RCM purchases
3.1(e)Non-GST outward supplies -- petroleum, alcohol, etc.
3.2Inter-state supplies to unregistered persons, composition taxpayers, UIN holders
4(A)ITC Available -- imports, RCM, ISD, other ITC
4(B)ITC Reversed -- Rule 42/43 reversals, others
4(C)Net ITC Available -- 4(A) minus 4(B)
4(D)Ineligible ITC -- as per Sec 17(5)
5.1Interest and late fee payable
6.1Tax payment -- IGST, CGST, SGST -- cash + ITC utilization

Key GSTR-1 tables:

TableMeaning
4A/4B/6B/6CB2B supplies (invoices, debit notes, credit notes)
5A/5BB2C inter-state (invoice value > INR 2.5 lakh)
7B2C other (intra-state and inter-state below INR 2.5 lakh, rate-wise)
6AExports (with payment / without payment of tax)
8A/8B/8C/8DNil-rated, exempted, and non-GST supplies
9BCredit notes / debit notes (unregistered)
11A/11BAmendments to prior period B2B / export invoices
12HSN-wise summary of outward supplies

Conservative defaults -- India-specific:

AmbiguityDefault
Unknown rate on a sale18%
Unknown VAT status of a purchaseNot deductible (no ITC)
Unknown counterparty stateSame state as client (intra-state, CGST+SGST)
Unknown B2B vs B2C status for buyerB2C (no GSTIN, no ITC for buyer)
Unknown business-use proportion (vehicle, phone, home office)0% recovery
Unknown SaaS billing entityReverse charge from non-resident (IGST)
Unknown blocked-input status (entertainment, personal use)Blocked under Sec 17(5)
Unknown whether transaction is in scopeIn scope
Unknown inter-state vs intra-stateIntra-state (CGST+SGST)

Red flag thresholds -- country slot values for reviewer brief:

ThresholdValue
HIGH single-transaction sizeINR 5,00,000
HIGH tax-delta on a single conservative defaultINR 25,000
MEDIUM counterparty concentration>40% of output OR input
MEDIUM conservative-default count>4 across the return
LOW absolute net GST positionINR 10,00,000

Section 2 -- Required inputs and refusal catalogue

Required inputs

Minimum viable -- bank statement for the month/quarter in CSV, PDF, Excel, or pasted text. Must cover the full filing period. Acceptable from any Indian bank: SBI, HDFC, ICICI, Axis, Kotak, PNB, Bank of Baroda, IndusInd, Yes Bank, IDFC First, or any other scheduled bank. Also acceptable: Razorpay, Paytm, or other payment processor settlement reports.

Recommended -- purchase and sales invoices for the period (especially for inter-state B2B, exports, and reverse charge), prior period GSTR-3B and GSTR-1 filed copies, GSTR-2B (auto-drafted ITC statement) from the GST portal, Form 26AS / AIS (for cross-verification of TDS and high-value transactions).

Ideal -- Tally ERP / Zoho Books / ClearTax / Busy Accounting export (trial balance + GST-ready transaction register), complete invoice register with HSN/SAC codes, GSTR-9 from prior year, e-invoicing JSON exports if applicable.

Refusal policy if minimum is missing -- SOFT WARN. If no bank statement or transaction data is available at all, hard stop. If bank statement only without invoices, proceed but record in the reviewer brief: "This GSTR-3B was produced from bank statement alone. The reviewer must verify, before approval, that ITC claims are supported by tax invoices appearing in GSTR-2B, that all inter-state vs intra-state classifications are correct, and that reverse-charge self-assessments match the supplier's invoice."

India-specific refusal catalogue

If any trigger fires, stop, output the refusal message verbatim, end the conversation. Refusal is a safety mechanism.

R-IN-1 -- Composition scheme taxpayer. Trigger: client is registered under composition scheme (Sec 10), or mentions CMP-08, GSTR-4, or turnover below INR 1.5 crore with simplified filing. Message: "Composition scheme taxpayers file GSTR-4 (annual) and CMP-08 (quarterly challan), not GSTR-3B/GSTR-1. They cannot claim ITC, cannot make inter-state supplies, and pay tax at flat rates (1% for traders/manufacturers, 5% for restaurants, 6% for service providers). This skill covers regular taxpayers only. Please use a qualified GST practitioner for composition scheme returns."

R-IN-2 -- Multi-state registration. Trigger: client has GSTINs in more than one state and asks to consolidate or cross-credit. Message: "Each state GSTIN is a separate taxpayer under GST law. Cross-state ITC utilization is not permitted. This skill handles a single GSTIN filing only. If you need to file for multiple GSTINs, process each separately. For ISD (Input Service Distributor) cross-charge scenarios, please use a qualified CA/GST practitioner."

R-IN-3 -- SEZ supplies (as supplier to SEZ). Trigger: client makes supplies to SEZ units or developers and asks about zero-rating, LUT filing, or refund of accumulated ITC specific to SEZ. Message: "SEZ supply documentation (endorsed invoices, SEZ authority endorsement, LUT/bond filing) requires fact-specific verification beyond this skill. Please use a qualified GST practitioner for SEZ supply compliance."

R-IN-4 -- E-commerce operator (TCS obligations). Trigger: client operates an e-commerce platform and must collect TCS under Sec 52, or is a supplier through e-commerce with specific compliance obligations. Message: "E-commerce operators have TCS collection, GSTR-8 filing, and platform-level compliance obligations that are outside the scope of this skill. Please use a qualified GST practitioner."

R-IN-5 -- Input Service Distributor (ISD). Trigger: client is registered as an ISD or needs to distribute common input services across multiple GSTINs. Message: "ISD distribution requires proportional credit allocation across GSTINs under CGST Rules. This skill covers single-GSTIN regular taxpayers only. Please use a qualified CA/GST practitioner for ISD compliance."


Section 3 -- Supplier pattern library (the lookup table)

This is the deterministic pre-classifier. When a transaction's counterparty matches a pattern in this table, apply the treatment from the table directly. Do not second-guess. Do not consult Tier 1 rules -- the table is authoritative for patterns it covers.

How to read this table. Match by case-insensitive substring on the counterparty name/description as it appears in the bank statement. If multiple patterns match, use the most specific. If none match, fall through to Tier 1 rules in Section 5.

3.1 Indian banks (fees exempt -- exclude)

PatternTreatmentNotes
SBI, STATE BANK OF INDIAEXCLUDE for bank charges/feesFinancial service, exempt under Notification 12/2017-CT(Rate)
HDFC BANK, HDFC BKEXCLUDE for bank charges/feesSame
ICICI BANK, ICICI BKEXCLUDE for bank charges/feesSame
AXIS BANKEXCLUDE for bank charges/feesSame
KOTAK MAHINDRA, KOTAK BKEXCLUDE for bank charges/feesSame
PNB, PUNJAB NATIONAL BANKEXCLUDE for bank charges/feesSame
BOB, BANK OF BARODAEXCLUDE for bank charges/feesSame
INDUSIND, YES BANK, IDFC FIRSTEXCLUDE for bank charges/feesSame
INTEREST, BYAJ, INT PAID, INT RECDEXCLUDEInterest income/expense, exempt financial service
LOAN, EMI, PERSONAL LOAN, HOME LOANEXCLUDELoan principal/EMI movement, not a supply
FD, FIXED DEPOSIT, RDEXCLUDEInvestment movement, not a supply

3.2 Government (exclude entirely -- not a supply)

PatternTreatmentNotes
GST PMT, GST PAYMENT, GST CHALLAN, GSTNEXCLUDETax payment to government
INCOME TAX, IT DEPT, TDS, ADVANCE TAX, CPC BANGALOREEXCLUDEDirect tax payment
MCA, ROC FEE, COMPANY AFFAIRSEXCLUDERegulatory fee
EPFO, PF, ESI, ESIC, PROVIDENT FUNDEXCLUDEStatutory social security contribution
PROFESSIONAL TAX, PT PAYMENTEXCLUDEState professional tax
STAMP DUTY, REGISTRATION FEE (govt)EXCLUDEGovernment fee, not a supply
MUNICIPAL, NAGAR NIGAM, PROPERTY TAXEXCLUDELocal body tax

3.3 Telecom and utilities (18%)

PatternTreatmentGSTR-3B TableNotes
JIO, RELIANCE JIO18% input, CGST+SGST or IGST4(A)Telecom service
AIRTEL, BHARTI AIRTEL18% input4(A)Telecom service
VI, VODAFONE IDEA18% input4(A)Telecom service
BSNL, MTNL18% input4(A)Government telecom, still taxable
TATA POWER, ADANI ELECTRICITY, BSES, BESCOM, MSEDCL18% input4(A)Electricity distribution (post-GST 2.0: electricity brought under GST at 18% for commercial/industrial consumers)
MAHANAGAR GAS, IGL, ADANI GAS5% input4(A)Piped natural gas for domestic/CNG at 5%
WATER SUPPLY, JALABOARDEXCLUDEMunicipal water, exempt

3.4 Insurance

PatternTreatmentNotes
LIC, LIFE INSURANCE CORPEXCLUDELife insurance premium -- exempt (pure life, term). Endowment/ULIP policies may have GST but ITC blocked under Sec 17(5)(d)
HDFC ERGO, ICICI LOMBARD, BAJAJ ALLIANZ18% -- but check Sec 17(5)(d)General insurance at 18%. ITC blocked unless: (i) government-mandated employee coverage, or (ii) used for making taxable supply of same category
STAR HEALTH, NIVA BUPA, CARE HEALTH18% -- but check Sec 17(5)(d)Health insurance at 18%. ITC blocked unless government-mandated employee coverage
NEW INDIA ASSURANCE, UNITED INDIA18% -- but check Sec 17(5)(d)Same treatment as HDFC Ergo

3.5 SaaS and cloud -- Indian entities (18%)

PatternBilling entityTreatmentNotes
AWS INDIA, AMAZON INTERNET SERVICESAmazon Internet Services Pvt Ltd (IN)18% IGST (if inter-state) or CGST+SGST (if same state)Check supplier GSTIN state code vs client state
GOOGLE INDIA, GOOGLE CLOUD INDIAGoogle India Pvt Ltd / Google Cloud India Pvt Ltd (IN)18%Check invoice for GSTIN
ZOHO, ZOHO CORPZoho Corporation Pvt Ltd (IN, Chennai)18% IGST or CGST+SGSTCheck state code
FRESHWORKSFreshworks Technologies Pvt Ltd (IN, Chennai)18%Same treatment
MICROSOFT INDIAMicrosoft Corporation India Pvt Ltd (IN)18%Check invoice for Indian GSTIN
CLEARTAX, CLEARClear (formerly ClearTax) (IN)18%Accounting/compliance SaaS

3.6 Non-resident SaaS (reverse charge under IGST Act Sec 5(3))

PatternBilling entityTreatmentNotes
NOTION, NOTION LABSNotion Labs Inc (US)RCM -- self-assess IGST 18% via cash ledgerReport in GSTR-3B Table 3.1(d). ITC claimable in 4(A)(3)
OPENAI, CHATGPTOpenAI Inc (US)RCM -- IGST 18%Same
GITHUB (US entity)GitHub Inc (US)RCM -- IGST 18%Check if billed by Indian or US entity
ANTHROPIC, CLAUDEAnthropic PBC (US)RCM -- IGST 18%Same
FIGMAFigma Inc (US)RCM -- IGST 18%Same
CANVACanva Pty Ltd (AU)RCM -- IGST 18%Non-resident, reverse charge
SLACK (US)Slack Technologies LLC (US)RCM -- IGST 18%If billed by US entity. Salesforce Ireland = check
HUBSPOT (US)HubSpot Inc (US)RCM -- IGST 18%Check billing entity
TWILIOTwilio Inc (US)RCM -- IGST 18%Same

3.7 Payment processors (18%)

PatternTreatmentNotes
RAZORPAY18% input (IGST or CGST+SGST)Payment gateway fees -- check GSTIN state code
PAYTM, ONE97 COMMUNICATIONS18% inputSame
STRIPE INDIA, STRIPE PAYMENTS INDIA18% inputIndian entity -- check invoice
STRIPE (US/IE entity)RCM -- IGST 18%Non-resident -- reverse charge if no Indian GSTIN
CASHFREE, INSTAMOJO, PHONEPE BUSINESS18% inputPayment processing service
PAYPAL (transaction fees from foreign entity)RCM -- IGST 18%PayPal Pte Ltd (SG) -- non-resident reverse charge
CCAVENUE, BILLDESK18% inputIndian payment processors

3.8 Travel (5% / 18%)

PatternTreatmentNotes
INDIGO, INTERGLOBE AVIATION5% (economy class)Domestic air travel economy = 5%. Business class = 18%. Check ticket class
AIR INDIA5% (economy) / 18% (business)Same split. International flights = zero-rated
SPICEJET, AKASA AIR, AIR ASIA INDIA5% (economy) / 18% (business)Same treatment
VISTARA, TATA SIA5% (economy) / 18% (business)Same
OLA, ANI TECHNOLOGIES5%Ride-hailing at 5% (non-AC auto/e-rickshaw may be exempt)
UBER INDIA5%Same as Ola
IRCTC, INDIAN RAILWAYS5%Rail transport of passengers. Sleeper/AC chair at 5%. Local suburban exempt
MAKEMYTRIP, GOIBIBO, YATRA18% on service fee; underlying transport at transport ratePlatform commission at 18%. Underlying ticket at 5%/18% per class
HOTELS, OYO, TAJ, ITC HOTELS, LEMON TREE18% (tariff > INR 7,500/night) or 5% (tariff <= INR 7,500, without ITC option)Check declared tariff

3.9 Restaurants (5% no ITC vs 18%)

PatternTreatmentNotes
SWIGGY5% (collected by platform)Restaurant service via e-commerce -- 5% with no ITC. Platform is liable to collect and remit GST
ZOMATO5% (collected by platform)Same as Swiggy
Restaurant (direct, non-hotel, non-AC)5% output (no ITC)Restaurant choosing 5% rate foregoes ITC
Restaurant (in hotel, tariff > INR 7,500)18% (with ITC)Hotel restaurant where declared room tariff > INR 7,500
DOMINOS, PIZZA HUT, MCDONALDS, KFC, BURGER KING5% (dine-in/takeaway)QSR chains at 5% without ITC
CLOUD KITCHEN, REBEL FOODS5% via platformSame treatment as Swiggy/Zomato delivery

3.10 Professional services (18%)

PatternTreatmentNotes
CA, CHARTERED ACCOUNTANT, [name] & ASSOCIATES18% input (CGST+SGST or IGST)Professional services. ITC available if used for taxable outward supply
CS, COMPANY SECRETARY18% inputSame
ADVOCATE, ADV, LAWYER, LAW FIRM18% -- RCM appliesLegal services by individual advocate/firm = reverse charge. Recipient pays GST
CONSULTANT, CONSULTANCY18% inputCheck if RCM applies (non-resident consultant = RCM)
ARCHITECT, INTERIOR DESIGNER18% inputForward charge from registered supplier

3.11 Rent

PatternTreatmentNotes
RENT (commercial property)18% input (CGST+SGST or IGST)Commercial property rent at 18%. ITC available
RENT (residential, to registered person for business)18% RCMFrom 18 Jul 2022, residential property rented to registered person = RCM on tenant. Tenant self-assesses 18%
RENT (residential, to unregistered person)EXCLUDEExempt. Not a taxable supply when tenant is unregistered
COWORKING, WEWORK, AWFIS, COWRKS, 91SPRINGBOARD18% inputCommercial workspace service at 18%

3.12 Salaries and wages (exclude entirely -- not a supply)

PatternTreatmentNotes
SALARY, WAGES, STIPEND, PAYROLLEXCLUDEEmployer-employee relationship. Schedule III -- not a supply
BONUS, GRATUITY, LEAVE ENCASHMENTEXCLUDESame
CONTRACTOR (individual, no GSTIN)EXCLUDE from GST; flag for TDSNot a GST supply if unregistered. May need 194C TDS

Section 4 -- Worked examples

These are six fully worked classifications drawn from a hypothetical HDFC Bank statement of a Mumbai-based self-employed software consultant (GSTIN: 27XXXXX1234X1Z5, Maharashtra). They illustrate the trickiest cases. Pattern-match against these when you encounter similar lines in any real statement.

Example 1 -- Non-resident SaaS reverse charge (Notion)

Input line: 05.01.2026 ; NOTION LABS INC DEBIT CARD ; DR ; USD 10.00 ; INR 840.00

Reasoning: Notion Labs Inc is a US entity (Section 3.6). No GST on the charge. This is an import of services -- the client must self-assess IGST at 18% under reverse charge (IGST Act Sec 5(3)). RCM liability paid via electronic cash ledger only. ITC claimable in the same period if conditions under Sec 16 are met. Net effect = zero (cash-neutral for fully taxable person).

Output:

DateCounterpartyGross (INR)NetGST self-assessedRateGSTR-3B Table (output)GSTR-3B Table (input)Default?Question?
05.01.2026NOTION LABS INC-840-840IGST 15118%3.1(d)4(A)(3)N--

Example 2 -- Indian SaaS, inter-state (AWS India)

Input line: 10.01.2026 ; AMAZON INTERNET SERVICES PVT LTD NEFT ; DR ; INR 23,600.00

Reasoning: Amazon Internet Services Pvt Ltd is registered in Telangana (GSTIN: 36XXXXXX). Client is in Maharashtra (27). Different states = inter-state = IGST at 18%. Invoice amount INR 23,600 is gross (INR 20,000 net + INR 3,600 IGST). ITC of INR 3,600 IGST claimable if reflected in GSTR-2B.

Output:

DateCounterpartyGross (INR)NetGST paidRateGSTR-3B TableDefault?Question?
10.01.2026AMAZON INTERNET SERVICES-23,600-20,000IGST 3,60018%4(A)(5)N--

Example 3 -- Domestic restaurant, blocked ITC (Swiggy)

Input line: 15.01.2026 ; BUNDL TECHNOLOGIES SWIGGY ; DR ; INR 450.00

Reasoning: Swiggy (Bundl Technologies) is a restaurant aggregator platform. Restaurant food at 5% -- but ITC on food and beverages is blocked under Sec 17(5)(b). The 5% GST is collected and remitted by the e-commerce platform. For the recipient (our client), no ITC is available regardless of business purpose. Exclude from ITC claim. The expense may still be deductible for income tax purposes if business-related.

Output:

DateCounterpartyGross (INR)NetGSTRateITC?Default?Question?
15.01.2026SWIGGY-450-42921 (5%)5%BLOCKED -- Sec 17(5)(b)Y"Was this a business meal or personal?"

Example 4 -- Legal services under reverse charge (Advocate)

Input line: 20.01.2026 ; ADV RAJESH SHARMA NEFT ; DR ; INR 50,000.00

Reasoning: Payment to an advocate for legal services. Under Notification 13/2017-CT(Rate) Sl. No. 2, legal services by an individual advocate or firm of advocates to any business entity attract reverse charge. The client (business entity) must self-assess GST at 18%. Since both advocate and client are in Maharashtra, this is intra-state: CGST 9% + SGST 9% on INR 50,000 = INR 9,000 total. Paid via cash ledger. ITC of INR 9,000 claimable if the legal service was for business purposes.

Output:

DateCounterpartyGross (INR)NetGST self-assessedRateGSTR-3B Table (output)GSTR-3B Table (input)Default?Question?
20.01.2026ADV RAJESH SHARMA-50,000-50,000CGST 4,500 + SGST 4,50018%3.1(d)4(A)(3)Y"Confirm advocate is in same state (intra-state) and not an employee"

Example 5 -- Domestic air travel, economy class

Input line: 22.01.2026 ; INTERGLOBE AVIATION INDIGO 6E-1234 ; DR ; INR 5,250.00

Reasoning: IndiGo domestic flight. Economy class domestic air travel attracts 5% GST (CGST 2.5% + SGST 2.5% or IGST 5%). Net = INR 5,000, GST = INR 250. ITC of INR 250 is available if the travel was for business purposes and not blocked under Sec 17(5)(e) (travel benefits to employees on vacation are blocked, but business travel by the proprietor is not LTC). Check: business class would be 18%.

Output:

DateCounterpartyGross (INR)NetGSTRateGSTR-3B TableDefault?Question?
22.01.2026INTERGLOBE AVIATION-5,250-5,0002505%4(A)(5)Y"Economy or business class? Business purpose?"

Example 6 -- Motor vehicle (personal car), hard block

Input line: 28.01.2026 ; MARUTI SUZUKI INDIA LTD NEFT ; DR ; INR 8,50,000.00

Reasoning: Car purchase payment. ITC on motor vehicles is hard-blocked under Sec 17(5)(a) unless the vehicle is used for: (i) further supply of vehicles, (ii) transportation of passengers, (iii) driving training, or (iv) transportation of goods. A software consultant does not qualify for any exception. Full ITC block regardless of business use. The GST paid (18% or 40% depending on vehicle type) is a cost to the business. Do not claim any ITC.

Output:

DateCounterpartyGross (INR)NetGSTRateITC?Default?Question?
28.01.2026MARUTI SUZUKI-8,50,000----18%/40%BLOCKED -- Sec 17(5)(a)Y"Motor vehicle: blocked. Is this for transport of goods/passengers as primary business?"

Section 5 -- Tier 1 classification rules (compressed)

Each rule states the legal source and the GSTR-3B table mapping. Apply silently if the data is unambiguous.

5.1 GST rate slabs (post-GST 2.0, effective 22 Sep 2025)

Legislation: CGST Act Sec 9; 56th GST Council; Notification 01/2017-CT(Rate) as amended.

Three active slabs plus nil/zero:

  • 5% (CGST 2.5% + SGST 2.5% / IGST 5%): packaged food, medicines, economy transport, insurance, EVs, restaurants (without ITC option), small hotels
  • 18% (CGST 9% + SGST 9% / IGST 18%): most goods and services -- IT, telecom, financial services, professional services, branded garments, consumer durables, cement, non-luxury automobiles, commercial rent
  • 40% (CGST 20% + SGST 20% / IGST 40%): demerit/luxury only -- aerated drinks, energy drinks, premium motor vehicles (SUVs >4m, >1500cc), online gaming/casinos/betting
  • 0% (nil/exempt): fresh food (milk, cereals, vegetables, fruits), healthcare, education
  • 0% (zero-rated): exports, SEZ supplies

Former 12% and 28% slabs abolished 22 Sep 2025. Items moved to 5% or 18% respectively.

5.2 CGST+SGST vs IGST determination

Legislation: CGST Act Sec 9; IGST Act Sec 5; IGST Act Chapter V (Place of Supply).

ScenarioTax type
Supplier state = Buyer state (intra-state)CGST + SGST (half rate each)
Supplier state = Buyer UT (intra-UT)CGST + UTGST
Supplier state != Buyer state (inter-state)IGST (full rate)
Import of goodsIGST (via Customs) + BCD (no ITC on BCD)
Import of servicesIGST under reverse charge
ExportZero-rated (IGST or under LUT)

Key determination: Compare first two digits of supplier GSTIN vs buyer GSTIN. If same state code = intra-state. If different = inter-state. If buyer has no GSTIN (B2C), use buyer's billing address to determine state.

5.3 Reverse charge on import of services

Legislation: IGST Act Sec 5(3); Sec 5(4).

ANY import of services where supplier is outside India and recipient is in India -- IGST must be self-assessed and paid by recipient under reverse charge. No threshold. Paid via electronic cash ledger only (ITC cannot be used to discharge RCM liability). ITC on the RCM payment is available in the same period if Sec 16 conditions are met. Net effect = zero for a fully taxable recipient.

Report: GSTR-3B Table 3.1(d) for output; Table 4(A)(3) for ITC.

5.4 Domestic reverse charge (specified services)

Legislation: CGST Act Sec 9(3); Notification 13/2017-CT(Rate).

Key RCM categories for freelancers/small businesses:

  • Legal services by individual advocate/firm of advocates
  • Services by director (not as employee) to company
  • Services by Goods Transport Agency (GTA) -- if GTA has not opted for forward charge
  • Sponsorship services to body corporate/partnership
  • Services by government/local authority to business entity
  • Security services from unincorporated supplier to registered person

Mechanics: self-assess at applicable rate, pay via cash ledger, report in 3.1(d), claim ITC in 4(A)(3).

5.5 E-invoicing (INR 5 crore threshold)

Legislation: CGST Rule 48(4); Notification 13/2020-CT and amendments.

If aggregate turnover in any FY from 2017-18 onwards exceeds INR 5 crore:

  • Mandatory e-invoice for all B2B supplies
  • Upload JSON to Invoice Registration Portal (IRP) at einvoice1.gst.gov.in
  • Receive IRN (Invoice Reference Number) + QR code
  • IRN + QR must appear on invoice
  • E-invoice auto-populates GSTR-1 and e-way bill Part A
  • 30-day reporting rule: taxpayers with AATO >= INR 10 crore must report within 30 days of invoice date (from 1 Apr 2025)
  • MFA mandatory for all GST portal access from 1 Apr 2025

5.6 ITC conditions (all four must be met)

Legislation: CGST Act Sec 16(2).

  1. Possession of tax invoice or debit note
  2. Receipt of goods or services
  3. Tax actually paid to government by supplier (reflected in GSTR-2B)
  4. Recipient has filed GSTR-3B

ITC cannot exceed amount in GSTR-2B. If supplier has not uploaded invoice, recipient CANNOT claim ITC.

Time limit: Earlier of 30 Nov of year following the FY, or date of filing GSTR-9 for that FY.

Non-payment reversal: If recipient does not pay supplier within 180 days of invoice date, ITC must be reversed. Re-claim upon payment.

5.7 Blocked credits -- Sec 17(5) (absolute blocks)

CategoryBlocked?Exception
Motor vehicles and conveyancesYESOnly if used for: further supply of vehicles, transport of passengers, driving training, transport of goods
Food, beverages, outdoor catering, beauty, health, cosmetic surgeryYESOnly if used for making outward taxable supply of same category, or as element of taxable composite/mixed supply
Club membership, health and fitness centreYESNone
Rent-a-cab, life insurance, health insuranceYESGovernment-mandated employee provision; or used for making taxable supply of same category
Travel benefits to employees on vacation (LTC/LTA)YESNone
Works contract for immovable property (not plant & machinery)YESInput service for further supply of works contract
Construction of immovable property on own account (not plant & machinery)YESNone
Personal consumptionYESNone
Goods lost, stolen, destroyed, written off, gifts, free samplesYESNone -- ITC must be reversed

5.8 ITC utilization order

Legislation: CGST Act Sec 49(5); Circular 98/17/2019-GST.

IGST Credit --> First against IGST liability
            --> Then against CGST liability
            --> Then against SGST/UTGST liability

CGST Credit --> First against CGST liability
            --> Then against IGST liability
            --> CANNOT be used against SGST/UTGST

SGST Credit --> First against SGST liability
            --> Then against IGST liability
            --> CANNOT be used against CGST

IGST credit must be fully exhausted before CGST or SGST credit is used against IGST liability.

5.9 ITC reversal -- Rule 42/43

Legislation: CGST Rules, Rule 42 (inputs/input services), Rule 43 (capital goods).

When inputs are used partly for taxable and partly for exempt supplies:

ITC to reverse = (Exempt turnover / Total turnover) x Common Credit

Capital goods: 5-year useful life. Monthly reversal = Total ITC / 60 x (exempt / total turnover).

5.10 Filing deadlines and late fees

ReturnDeadlineLate fee (with tax liability)Late fee (nil)
GSTR-3B (monthly)20th of following monthINR 50/day (max INR 10,000)INR 20/day (max INR 500)
GSTR-1 (monthly)11th of following monthINR 50/day (max INR 10,000)INR 50/day (max INR 10,000)
GSTR-931st December following FYINR 200/day (max 0.5% of turnover)Same

Interest on late payment: 18% per annum on net cash liability. Excess ITC claimed and utilized: 24% per annum.

5.11 Exports -- two options

Legislation: IGST Act Sec 16(3); CGST Rules, Rule 96/96A.

OptionMechanismRefund
Export with payment of IGSTCharge IGST on invoiceAutomatic refund via shipping bill (Rule 96)
Export under LUT (without tax)File Letter of Undertaking annually (RFD-11), invoice at 0%Claim refund of accumulated ITC (Rule 89, RFD-01)

Report in GSTR-3B Table 3.1(b). GSTR-1 Table 6A.

5.12 E-way bill

Legislation: CGST Rules, Rule 138.

Required for movement of goods where consignment value > INR 50,000. Validity: 1 day per 200 km. Generated on ewaybillgst.gov.in. Not applicable to services.

5.13 HSN/SAC on invoices

TurnoverHSN digits required
Up to INR 5 crore4-digit HSN on B2B invoices
Above INR 5 crore6-digit HSN on all invoices

HSN = goods (based on WCO classification). SAC = services (starts with 99xxxx).

5.14 Compensation cess -- abolished

Abolished for non-tobacco items from 22 Sep 2025. Abolished for tobacco/pan masala from 1 Feb 2026 (replaced by Health Security and National Security Cess on production capacity). Do NOT apply compensation cess to any invoice dated on or after these dates.

5.15 QRMP scheme

Legislation: CGST Rule 61A; Notification 84/2020-CT.

Eligible if aggregate turnover <= INR 5 crore in preceding FY. GSTR-1 and GSTR-3B filed quarterly. Tax paid monthly via PMT-06 by 25th of following month. Invoice Furnishing Facility (IFF) available for optional B2B invoice upload in months 1 and 2 of quarter (max INR 50 lakh/month).


Section 6 -- Tier 2 catalogue (compressed)

For each ambiguity type: pattern, why the bank statement is insufficient, conservative default, question for the structured form.

6.1 Vehicle costs (petrol/diesel)

Pattern: HPCL, BPCL, IOCL, SHELL, petrol pump, fuel station, toll charges (FASTag/NHAI). Why insufficient: vehicle type and business-use proportion unknown. If vehicle is a car -> ITC on the car itself is blocked under Sec 17(5)(a), and fuel for a blocked vehicle is also typically blocked. If commercial vehicle (delivery van, truck) -> ITC available. Default: 0% recovery. Question: "Is this fuel for a car (ITC blocked) or a commercial vehicle used for business? What percentage is business use?"

6.2 Restaurants via platforms (Swiggy/Zomato)

Pattern: SWIGGY, ZOMATO, BUNDL TECHNOLOGIES, ZOMATO LTD, food delivery charges. Why insufficient: personal vs business meal unknown. GST at 5% is collected by the platform (e-commerce operator liable from 1 Jan 2022). ITC on food is blocked under Sec 17(5)(b) regardless. Default: no ITC claim. Expense may still be income tax deductible if business purpose established. Question: "Was this a business meal (e.g., client meeting) or personal? (Note: ITC is blocked either way -- this is for income tax records.)"

6.3 Home office (rent/utilities)

Pattern: rent payment, electricity bill, internet bill from residential address. Why insufficient: proportion of business use unknown. Residential rent to registered person triggers RCM at 18% from 18 Jul 2022 -- but the ITC on residential rent for personal use is blocked under Sec 17(5)(g). Mixed use requires apportionment but lacks clear methodology. Default: 0% ITC recovery on residential expenses. Question: "Do you work from home? What percentage of the property is used exclusively for business? Is the rent in your personal name or business name?"

6.4 Cash withdrawals

Pattern: ATM, CASH WDL, CASH WITHDRAWAL. Why insufficient: unknown what cash was spent on. Cash expenses need invoices for ITC. Default: exclude as owner drawing. Question: "What was the cash used for? Do you have invoices for any cash purchases?"

6.5 Mixed B2B/B2C sales (GSTIN determination)

Pattern: incoming payments from individuals or entities where GSTIN is unknown. Why insufficient: B2B (with GSTIN) requires per-invoice reporting in GSTR-1 Table 4A. B2C inter-state above INR 2.5 lakh requires Table 5A. B2C below threshold goes to Table 7 (rate-wise summary). Without knowing if buyer has GSTIN, cannot determine correct GSTR-1 table. Default: B2C (no GSTIN). Question: "For each sale: does the buyer have a GSTIN? If yes, what is it?"

6.6 Inter-state vs intra-state (counterparty location)

Pattern: payments to/from entities where state is unclear from bank statement description. Why insufficient: CGST+SGST vs IGST determination depends on comparing supplier and buyer state codes. Wrong determination = wrong tax heads = demand notice risk. Default: intra-state (same state as client) = CGST+SGST. Question: "Where is [counterparty] located? Same state as you, or a different state? If B2B, what is their GSTIN?"

6.7 Digital services from abroad (reverse charge -- is it really B2B?)

Pattern: foreign SaaS, cloud services, streaming subscriptions where business vs personal use is ambiguous. Why insufficient: RCM on import of services applies only when the service is received "in relation to business or commerce." Personal subscriptions (Netflix, Spotify personal) are not subject to RCM -- the foreign OIDAR supplier registers and pays under Simplified Registration (IGST Sec 14). Default: if the subscription appears on a business bank statement, treat as business use -> RCM applies. Question: "Is [service] used for business or personal purposes? If personal, it should not be on the business bank statement."


Section 7 -- Excel working paper template (India-specific)

Sheet "Transactions"

Columns:

  • A: Date
  • B: Counterparty / Description
  • C: Debit/Credit indicator
  • D: Gross amount (INR)
  • E: Net amount (INR)
  • F: GST amount (INR)
  • G: GST rate (0%, 5%, 18%, 40%, RCM, Exempt, Excluded)
  • H: Tax type (CGST+SGST / IGST / RCM-IGST / RCM-CGST+SGST / Nil / Excluded)
  • I: GSTR-3B table reference (3.1(a), 3.1(b), 3.1(c), 3.1(d), 4(A), 4(D), Excluded)
  • J: GSTR-1 table reference (4A, 5A, 7, 6A, 8A, Excluded)
  • K: Default? (Y/N)
  • L: Question / Notes

Use blank for excluded transactions in columns G-J.

Sheet "GSTR-3B Summary"

One row per table. Column A = table number, Column B = description, Column C = taxable value, Column D = IGST, Column E = CGST, Column F = SGST.

| 3.1(a) | Outward taxable (other) | =SUMIFS(...) | ... |
| 3.1(b) | Outward taxable (zero-rated) | =SUMIFS(...) | ... |
| 3.1(c) | Other outward (nil/exempt) | =SUMIFS(...) | ... |
| 3.1(d) | Inward (reverse charge) | =SUMIFS(...) | ... |
| 4(A)   | ITC Available | =SUMIFS(...) | ... |
| 4(B)   | ITC Reversed | =SUMIFS(...) | ... |
| 4(C)   | Net ITC | =4(A)-4(B) | ... |
| 4(D)   | Ineligible ITC (Sec 17(5)) | =SUMIFS(...) | ... |

Sheet "Tax Computation"

Output tax liability:
  IGST payable on outward supplies = [from 3.1(a) IGST column]
  CGST payable = [from 3.1(a) CGST column]
  SGST payable = [from 3.1(a) SGST column]
  Add: RCM liability (IGST/CGST/SGST) = [from 3.1(d)]

Less: ITC utilized (per utilization order in Section 5.8):
  IGST credit applied -> IGST -> CGST -> SGST
  CGST credit applied -> CGST -> IGST
  SGST credit applied -> SGST -> IGST

Net payable via cash = Output - ITC utilized

Color and formatting conventions

Blue for hardcoded values from bank statement (columns A-D). Black for formulas. Green for cross-sheet references. Yellow background for any row where Default? = "Y". Red text for any blocked ITC row (Sec 17(5)).

Mandatory recalc step

After building the workbook, run:

python /mnt/skills/public/xlsx/scripts/recalc.py /mnt/user-data/outputs/india-gst-<period>-working-paper.xlsx

Check the JSON output. If status is errors_found, fix the formulas and re-run.


Section 8 -- Indian bank statement reading guide

Follow the universal exclusion rules, plus these India-specific patterns.

HDFC Bank statement format

Typical CSV columns: Date, Narration, Chq/Ref No, Value Dt, Withdrawal Amt, Deposit Amt, Closing Balance. Date format: DD/MM/YY or DD/MM/YYYY. Narration field contains the counterparty info -- often cryptic: "NEFT/RTGS/IMPS-[IFSC]-[Sender name]", "UPI-[UPI ID]-[Name]", "POS [Merchant]-[Terminal ID]", "ATM-SELF", "BIL/ONL/[Biller name]".

HDFC narration parsing rules:

  • NEFT-UTIB0000XXX-JOHN DOE -> payment to/from John Doe via Axis Bank
  • UPI-rajesh@okhdfcbank-RAJESH KUMAR -> UPI payment to/from Rajesh Kumar
  • POS 123456789012 AMAZON -> card purchase at Amazon
  • BIL/ONL/AIRTEL -> online bill payment to Airtel
  • INT.PD -> interest paid (exclude)
  • CHG-GST or SERVICE CHARGES -> bank charges (exclude, exempt)

SBI statement format

Typical columns: Txn Date, Value Date, Description, Ref No/Cheque No, Debit, Credit, Balance. Description format: "INB/NEFT/[Ref]-[Name]", "ATM/SELF/[Branch]", "UPI/[ID]/[Name]", "SI-[Standing Instruction]".

ICICI Bank statement format

Typical columns: S No, Value Date, Transaction Date, Cheque Number, Transaction Remarks, Withdrawal Amount (INR), Deposit Amount (INR), Balance (INR). Remarks format: "NEFT-[IFSC]-[Name]", "UPI/[Ref]/[Name]", "MMT/IMPS/[Ref]/[Name]", "POS/[Merchant]/[Location]".

Common patterns across all Indian bank statements

UPI payments: Most common. Format varies but always contains "UPI" and a UPI ID or reference. The counterparty name is usually extractable. UPI to individuals without GSTIN -> likely personal or unregistered supplier -> Tier 2 question needed.

NEFT/RTGS/IMPS: Business payments. IFSC code in the narration can identify the counterparty bank branch. Large RTGS payments (> INR 2 lakh) are likely business transactions.

Card transactions (POS/online): Merchant name is embedded but often truncated. "AMAZON", "FLIPKART", "SWIGGY" are recognizable. "POS 4XXXXX" with no name -> ask client.

Standing instructions (SI/ECS/NACH): Recurring debits for EMI, insurance, subscriptions. Pattern: "ECS/NACH-[Mandate]-[Payee]". Common: LIC (insurance), HDFC HOME LOAN (EMI), SIP (mutual fund).

Internal transfers and exclusions:

  • Own-account transfers between savings/current accounts: "TRF-OWN", "SELF TRANSFER", "FD CREATION"
  • Mutual fund SIPs: "BSE-MF-[Fund name]" -> investment, exclude
  • FD maturity/creation: "FD-[number]" -> exclude
  • ATM self-withdrawal: "ATM-SELF", "ATM WDL" -> exclude as drawing

Refunds and reversals: "REVERSAL", "REFUND", "RETURN-NEFT". Book as negative in the same classification as the original transaction. Correct in the period booked, not by amending the original period.

Salary credits (if client has employees): "PAYROLL", "SALARY-[month]", outgoing to multiple individuals on same date. Exclude -- not a supply (Schedule III).

Loan disbursement/repayment: "LOAN DISB", "EMI-[Account]". Exclude -- not a supply.

Foreign currency transactions: Some banks show forex in narration: "FCY-USD-[amount]". Convert to INR at the transaction date rate shown on the statement. Note the rate in column L.


Section 9 -- Onboarding fallback (only when inference fails)

The workflow mandates inferring the client profile from the data first and only confirming with the client when inference fails. The questionnaire below is a fallback.

9.1 Legal name and GSTIN

Inference rule: GSTIN sometimes appears in payment descriptions, especially in NEFT narrations. Extract and validate the 15-digit format (2 state code + 10 PAN + entity code + Z + checksum). Fallback question: "What is your GSTIN? (15-digit alphanumeric, e.g. 27AAPFU0939F1Z5)"

9.2 Registration type

Inference rule: if client is asking for GSTR-3B/GSTR-1, they are regular (non-composition). If they mention CMP-08 or GSTR-4 -> R-IN-1 refuses. Fallback question: "Are you a regular GST taxpayer or under the composition scheme?"

9.3 State of registration

Inference rule: first two digits of GSTIN. Also inferable from the bank branch location in IFSC codes. Fallback question: "Which state is your GST registration in?"

9.4 Filing period and frequency

Inference rule: first and last transaction dates on the bank statement. Monthly filers: single month. QRMP filers: full quarter. Fallback question: "Which period does this cover? Are you a monthly filer or quarterly (QRMP)?"

9.5 Business activity

Inference rule: counterparty mix, sales descriptions, HSN/SAC on invoices. IT/software, consulting, trading, manufacturing are recognizable from transaction patterns. Fallback question: "In one sentence, what does the business do?"

9.6 Inter-state supplies

Inference rule: if outward payments or receipts involve GSTINs from different states or IGST appears on invoices. Fallback question: "Do you make sales to buyers in other states? If so, which states?"

9.7 Exports

Inference rule: foreign currency receipts, forex conversion entries, "FIRC" or "EXPORT" in narration. Fallback question: "Do you export goods or services? If so, do you have a Letter of Undertaking (LUT) filed for this financial year?"

9.8 Reverse charge purchases

Inference rule: payments to advocates, GTA, foreign services, directors. Fallback question: "Do you receive any services from advocates, goods transport agencies, or foreign suppliers? Do you have non-employee directors?"

9.9 E-invoicing applicability

Inference rule: aggregate turnover from prior year GSTR-9 or from client's stated turnover. Fallback question: "Has your aggregate turnover exceeded INR 5 crore in any financial year since 2017-18?"

9.10 ITC brought forward

Inference rule: not inferable from a single period statement. Always ask. Question: "Do you have any ITC balance carried forward from the previous period? (IGST, CGST, SGST amounts separately)"


Section 10 -- Reference material

Validation status

This skill is v2.0, rewritten in April 2026 to align with the Malta v2.0 three-tier architecture (Quick reference, Supplier pattern library, Worked examples, Tier 1/Tier 2 split). It supersedes v1.0 (standalone monolithic skill). The India-specific content (rate structure, GSTR-3B/GSTR-1 table mappings, blocked credits, reverse charge, e-invoicing, e-way bill) has been compiled from the CGST Act 2017, IGST Act 2017, CGST Rules 2017, and CBIC notifications/circulars. Post-GST 2.0 rate rationalization (56th GST Council, 22 Sep 2025) is reflected.

Sources

Primary legislation:

  1. Central Goods and Services Tax Act, 2017 (CGST Act) -- https://cbic-gst.gov.in
  2. Integrated Goods and Services Tax Act, 2017 (IGST Act) -- https://cbic-gst.gov.in
  3. CGST Rules, 2017 -- https://cbic-gst.gov.in
  4. State Goods and Services Tax Acts (each state)
  5. Goods and Services Tax (Compensation to States) Act, 2017 (abolished 2025/2026)

Key notifications: 6. Notification 01/2017-CT(Rate) -- GST rate schedule for goods (as amended by GST 2.0) 7. Notification 11/2017-CT(Rate) -- GST rate schedule for services (as amended) 8. Notification 12/2017-CT(Rate) -- Exempt services list 9. Notification 13/2017-CT(Rate) -- Reverse charge on specified services 10. Notification 13/2020-CT -- E-invoicing applicability 11. Notification 84/2020-CT -- QRMP scheme 12. Notification 02/2025 -- Compensation cess abolition (non-tobacco)

Key circulars: 13. Circular 98/17/2019-GST -- ITC utilization order 14. Circular 140/10/2020-GST -- Director services RCM clarification 15. Circular 164/20/2021-GST -- Restaurant composite/mixed supply

Portals: 16. GST Common Portal -- https://gst.gov.in 17. E-Invoice Portal -- https://einvoice1.gst.gov.in 18. E-Way Bill Portal -- https://ewaybillgst.gov.in

Known gaps

  1. The supplier pattern library covers common Indian vendors but does not cover every regional vendor or local supplier. Add patterns as they emerge.
  2. Worked examples are drawn from a hypothetical Mumbai-based IT consultant. They do not cover manufacturing, trading, or hospitality specifically. A v2.1 should add sector-specific examples.
  3. HSN/SAC classification requires looking up the master schedule -- this skill does not contain the full HSN/SAC master. Flag unknown classifications as [T2].
  4. Place of supply for services is frequently disputed (IGST Act Sec 12/13). Complex scenarios involving multiple states or cross-border elements should be flagged [T2].
  5. The GST 2.0 rate rationalization (56th GST Council, 22 Sep 2025) abolished the 12% and 28% slabs. Some transitional edge cases may exist for invoices straddling the effective date.
  6. Health Security and National Security Cess (replacing compensation cess on tobacco/pan masala from 1 Feb 2026) is not detailed in this skill. Flag as [T3] if encountered.
  7. The e-invoicing threshold (INR 5 crore) and 30-day reporting rule (INR 10 crore AATO) are as of April 2026. Verify for future periods.
  8. ITC reversal calculations under Rule 42/43 require annual reconciliation in GSTR-9. This skill covers the monthly computation but not the annual true-up.

PROHIBITIONS [T1]

  • NEVER allow ITC on blocked credits under Sec 17(5) -- absolute blocks regardless of business use.
  • NEVER apply intra-state rates (CGST+SGST) to inter-state supplies, or vice versa.
  • NEVER let AI guess HSN/SAC codes -- classification must be verified against the HSN/SAC master.
  • NEVER allow ITC claims that do not appear in GSTR-2B.
  • NEVER discharge RCM liability using ITC -- must be paid via electronic cash ledger only.
  • NEVER allow ITC beyond the time limit (30 Nov of following FY).
  • NEVER classify a mixed supply as composite to achieve a lower rate.
  • NEVER ignore the ITC utilization order (IGST must be exhausted first).
  • NEVER allow e-invoicing-applicable businesses to issue invoices without IRN/QR code.
  • NEVER assume export status without LUT filing or IGST payment proof.
  • NEVER compute any number -- all arithmetic is handled by the deterministic engine, not Claude.

Change log

  • v2.0 (April 2026): Full rewrite to Malta v2.0 architecture. Quick reference with GSTR-3B/GSTR-1 table structure moved to top (Section 1). Supplier pattern library added with 12 sub-tables covering Indian banks, government, telecom, insurance, SaaS, non-resident SaaS, payment processors, travel, restaurants, professional services, rent, salaries (Section 3). Six worked examples from hypothetical HDFC Bank statement (Section 4). Tier 1 rules compressed with post-GST 2.0 rates (Section 5). Tier 2 catalogue with 7 ambiguity types (Section 6). Excel working paper template (Section 7). Indian bank statement reading guide covering HDFC, SBI, ICICI formats (Section 8). Onboarding moved to fallback with inference rules (Section 9). Five India-specific refusals: R-IN-1 (composition), R-IN-2 (multi-state), R-IN-3 (SEZ), R-IN-4 (e-commerce operator), R-IN-5 (ISD).
  • v1.0 (April 2026): Initial skill. Standalone monolithic document covering CGST/IGST Acts, rate classification, return forms, ITC rules, blocked credits, reverse charge, e-invoicing, e-way bill, composition scheme, edge cases, and test suite. Compiled from deep research verification.

Self-check (v2.0 of this document)

  1. Quick reference at top with GSTR-3B table and conservative defaults: yes (Section 1).
  2. Supplier library as literal lookup tables: yes (Section 3, 12 sub-tables).
  3. Worked examples drawn from hypothetical HDFC Bank statement: yes (Section 4, 6 examples).
  4. Tier 1 rules compressed with post-GST 2.0 rates (5%/18%/40%): yes (Section 5, 15 rules).
  5. Tier 2 catalogue compressed with inference rules: yes (Section 6, 7 items).
  6. Excel template specification with mandatory recalc: yes (Section 7).
  7. Onboarding as fallback only, inference rules first: yes (Section 9, 10 items).
  8. All 5 India-specific refusals present: yes (Section 2, R-IN-1 through R-IN-5).
  9. Reference material at bottom: yes (Section 10).
  10. Blocked credits (Sec 17(5)) hard-block explicit: yes (Section 5.7 + Examples 3, 6).
  11. Motor vehicle hard-block explicit: yes (Section 5.7 + Example 6).
  12. RCM on import of services explicit: yes (Section 5.3 + Example 1).
  13. RCM on domestic specified services (advocate) explicit: yes (Section 5.4 + Example 4).
  14. CGST+SGST vs IGST determination explicit: yes (Section 5.2 + Example 2).
  15. Restaurant/food ITC block explicit: yes (Section 5.7 + Example 3).

End of India GST Return Skill v2.0


Disclaimer

This skill and its outputs are provided for informational and computational purposes only and do not constitute tax, legal, or financial advice. Open Accountants and its contributors accept no liability for any errors, omissions, or outcomes arising from the use of this skill. All outputs must be reviewed and signed off by a qualified professional (such as a CPA, EA, tax attorney, or equivalent licensed practitioner in your jurisdiction) before filing or acting upon.

The most up-to-date, verified version of this skill is maintained at openaccountants.com. Log in to access the latest version, request a professional review from a licensed accountant, and track updates as tax law changes.

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