Iowa Individual Income Tax Return (Form IA 1040) for sole proprietors and single-member LLCs. Covers the flat 3.8% rate (tax year 2025/2026), Iowa net income computation from federal AGI, Iowa standard deduction, and estimated tax. Iowa completed its historic flat-tax reform in 2025. Trigger: taxpayer is an Iowa resident or has Iowa-source income.
Written by the OpenAccountants team. Written by the OpenAccountants team from the official sources it cites.
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Every figure is drawn from this Guide and cited to its source.
Flat rate applicability
3.8%Iowa Code § 422.5, as amended by SF 2442 (signed May 2024)
Single / Married filing separately
$2,130
Married filing jointly / Head of household
$5,240
Personal exemption credit (per exemption)
$40
Single (under 65)
$9,000
Single (65+)
$24,000
Married filing jointly (under 65)
$13,500
Married filing jointly (65+)
$32,000
Nonresident filing threshold
Nonresidents must file if Iowa-source income ≥ $1,000.
Federal NOL deduction add-back
Federal net operating loss (NOL) deduction claimed on federal return (Iowa has its own NOL rules)
Capital gain deduction add-back
Capital gain deduction claimed on IA 1040 (add back if not qualifying)
Iowa capital gain deduction
Qualifying sales of real property used in farming/business (100% exclusion if held 10+ years and certain conditions met)
Pension/retirement income exclusion
Up to $6,000 per person ($12,000 MFJ) for taxpayers age 55+
Social Security exclusion
Iowa fully excludes Social Security from taxable income
Military retirement pay exclusion
Fully excluded
Interest on U.S. government obligations
Excluded from Iowa income
Standard or itemized deduction
Iowa standard deduction OR Iowa itemized deductions
QBI deduction
Qualified business income (QBI) deduction (Iowa allows the federal §199A deduction as a separate line item)
Iowa tax computation formula
Federal AGI ± Iowa adjustments = Iowa net income → minus Iowa standard/itemized deduction → minus QBI deduction = Iowa taxable income → × 3.8% = Iowa tax → minus credits (including personal exemption credits).
QBI conformity rule
Iowa specifically allows the federal QBI deduction (§199A) as a below-the-line deduction on Form IA 1040, Line 1e. This reduces Iowa taxable income.
SE health insurance deduction treatment
Already reflected in federal AGI. Flows through to Iowa automatically.
Retirement contributions treatment
Already reflected in federal AGI. No Iowa add-back required.
Home office deduction treatment
Already reflected in Schedule C → federal AGI. Flows through automatically.
Estimated tax requirement
Self-employed individuals must make quarterly estimated payments if they expect to owe $200 or more.
Voucher due dates
April 30, June 30, September 30, January 31.
Safe harbor
No penalty if payments equal at least 90% of current year tax OR 100% of prior year tax (110% if prior year Iowa AGI > $150,000).
Capital gain deduction eligibility
Sole proprietors who sell qualifying Iowa business assets held for 10+ years may exclude 100% of the gain. This is a significant benefit for long-held business property.
Requirement - real property
Asset must be real property used in a farming operation, or
Requirement - qualifying stock/interest
Asset must be qualifying business stock/partnership interest
Other requirements
Various holding period and material participation requirements apply
IA-IT-1.01
Iowa tax = Iowa taxable income × 3.8%
IA-IT-1.02
Iowa starts from federal AGI (Form 1040, Line 11)
IA-IT-1.03
Iowa allows federal QBI deduction (§199A) as separate deduction on IA 1040
IA-IT-1.04
Social Security benefits are fully excluded from Iowa income
IA-IT-1.05
Filing deadline is April 30 (not April 15)
IA-IT-1.06
No local/city income taxes in Iowa
IA-IT-1.07
Iowa inheritance tax repealed effective January 1, 2025
IA-IT-1.08
Personal exemption credit: $40 per exemption (non-refundable)
IA-IT-1.09
Iowa does not conform to federal NOL rules — separate Iowa NOL computation required
IA-IT-2.01
Iowa capital gain deduction eligibility
IA-IT-2.02
Iowa vs. federal itemized deductions
IA-IT-2.03
Part-year resident allocation (Schedule IA 126)
IA-IT-2.04
Iowa NOL carryover
IA-IT-2.05
Pension/retirement exclusion eligibility
IA-IT-2.06
Alternate tax computation
IOWA DEPT OF REVENUE
Iowa income tax payment
STATE OF IOWA TAX
Iowa estimated tax payment
IA TAX REFUND
Iowa income tax refund
IDR IOWA PMT
Iowa Department of Revenue payment
IA 1040, Line 1
Federal Form 1040, Line 11 (AGI)
IA 1040, Lines 1a–1c
Iowa adjustments (additions/subtractions)
IA 1040, Line 1d
Iowa standard or itemized deduction
IA 1040, Line 1e
QBI deduction (federal §199A amount)
IA 1040, Line 4
Iowa taxable income
IA 1040, Line 5
Iowa tax (Line 4 × 3.8%)
Form IA 1040-ES
Quarterly estimated payments
Schedule IA 126
Nonresident/part-year income allocation
Schedule IA 1040C
Itemized deductions
R-IA-01
Corporate income taxSeparate return and rules
R-IA-02
Part-year / nonresident allocationComplex allocation via Schedule IA 126
R-IA-03
Iowa NOL computationComplex multi-year tracking required
R-IA-04
Franchise tax (financial institutions)Industry-specific
R-IA-05
Withholding taxEmployer obligation
R-IA-06
Property tax credits (Homestead)Separate application process
R-IA-07
Capital gain deduction detailed analysisComplex holding period and participation rules
Rendered from the canonical facts model. General reference only — confirm with a qualified professional before acting.
Scope. This skill covers Iowa individual income tax for self-employed individuals and sole proprietors filing Form IA 1040. Iowa has a flat 3.8% rate — the result of landmark tax reform (SF 2442, 2024) that completed the transition from a multi-bracket system. Quality tier. Q3 — AI-drafted with citations. Must be reviewed by a qualified professional before use.
Metadata table
| Field | Value |
|---|---|
| Jurisdiction | US-IA (Iowa) |
| Tax authority | Iowa Department of Revenue (IDR) |
| Filing portal | Iowa eFile & Pay |
| Legislation citation | Iowa Code Chapter 422 (Individual Income Tax) |
| Primary form | Form IA 1040 (Individual Income Tax Return) |
| Filing deadline | April 30, 2026 (for tax year 2025) |
| Extension | Automatic 6-month extension to October 31; tax must be paid by April 30 |
| Version | 0.1 |
| Generated date | May 22, 2026 |
| Validation status | AI-drafted — Q3 |
Tax year 2025 rate table (Iowa Code § 422.5, as amended by SF 2442 (signed May 2024))
| Rate | Applies to |
|---|---|
| 3.8% (flat) | All Iowa taxable income |
Historical context: Iowa transitioned from a 4-bracket progressive system (4.4%–5.7% in 2024) to a single 3.8% flat rate in 2025, making it the lowest flat income tax rate in the Midwest.
Standard deduction table
| Filing status | Standard deduction |
|---|---|
| Single / Married filing separately | $2,130 |
| Married filing jointly / Head of household | $5,240 |
Personal exemption credit table
| Item | Amount |
|---|---|
| Personal exemption credit (per exemption) | $40 |
Filing thresholds table
| Filing status | Net income threshold |
|---|---|
| Single (under 65) | $9,000 |
| Single (65+) | $24,000 |
| Married filing jointly (under 65) | $13,500 |
| Married filing jointly (65+) | $32,000 |
Starting point: Iowa begins with federal adjusted gross income (AGI) from federal Form 1040, Line 11. However, Iowa then applies its own set of adjustments that differ significantly from the federal below-the-line computation.
After computing Iowa net income, subtract:
Note: Iowa's due dates differ from federal (April 30, not April 15).
Tier 1 rules table
| Rule ID | Rule |
|---|---|
| IA-IT-1.01 | Iowa tax = Iowa taxable income × 3.8% |
| IA-IT-1.02 | Iowa starts from federal AGI (Form 1040, Line 11) |
| IA-IT-1.03 | Iowa allows federal QBI deduction (§199A) as separate deduction on IA 1040 |
| IA-IT-1.04 | Social Security benefits are fully excluded from Iowa income |
| IA-IT-1.05 | Filing deadline is April 30 (not April 15) |
| IA-IT-1.06 | No local/city income taxes in Iowa |
| IA-IT-1.07 | Iowa inheritance tax repealed effective January 1, 2025 |
| IA-IT-1.08 | Personal exemption credit: $40 per exemption (non-refundable) |
| IA-IT-1.09 | Iowa does not conform to federal NOL rules — separate Iowa NOL computation required |
Tier 2 rules table
| Rule ID | Rule | Judgment needed |
|---|---|---|
| IA-IT-2.01 | Iowa capital gain deduction eligibility | Verify holding period, material participation, and asset type requirements |
| IA-IT-2.02 | Iowa vs. federal itemized deductions | Iowa may differ on certain itemized deductions; compare totals |
| IA-IT-2.03 | Part-year resident allocation (Schedule IA 126) | Prorate income for period of Iowa residency |
| IA-IT-2.04 | Iowa NOL carryover | Iowa has different NOL rules than federal; requires separate tracking |
| IA-IT-2.05 | Pension/retirement exclusion eligibility | Verify age 55+ and qualifying income types |
| IA-IT-2.06 | Alternate tax computation | Some taxpayers may owe less using the alternate tax method; compare both |
Supplier pattern library table
| Pattern on bank statement | Likely meaning |
|---|---|
| IOWA DEPT OF REVENUE | Iowa income tax payment |
| STATE OF IOWA TAX | Iowa estimated tax payment |
| IA TAX REFUND | Iowa income tax refund |
| IDR IOWA PMT | Iowa Department of Revenue payment |
Form mapping table
| Iowa Form | Federal equivalent / Input |
|---|---|
| IA 1040, Line 1 | Federal Form 1040, Line 11 (AGI) |
| IA 1040, Lines 1a–1c | Iowa adjustments (additions/subtractions) |
| IA 1040, Line 1d | Iowa standard or itemized deduction |
| IA 1040, Line 1e | QBI deduction (federal §199A amount) |
| IA 1040, Line 4 | Iowa taxable income |
| IA 1040, Line 5 | Iowa tax (Line 4 × 3.8%) |
| Form IA 1040-ES | Quarterly estimated payments |
| Schedule IA 126 | Nonresident/part-year income allocation |
| Schedule IA 1040C | Itemized deductions |
Refusal catalogue table
| Refusal ID | Topic | Reason |
|---|---|---|
| R-IA-01 | Corporate income tax | Separate return and rules |
| R-IA-02 | Part-year / nonresident allocation | Complex allocation via Schedule IA 126 |
| R-IA-03 | Iowa NOL computation | Complex multi-year tracking required |
| R-IA-04 | Franchise tax (financial institutions) | Industry-specific |
| R-IA-05 | Withholding tax | Employer obligation |
| R-IA-06 | Property tax credits (Homestead) | Separate application process |
| R-IA-07 | Capital gain deduction detailed analysis | Complex holding period and participation rules |
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.
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