Use this skill whenever asked about Missouri individual income tax for self-employed persons, sole proprietors, or single-member LLCs. Trigger on phrases like "Missouri income tax", "MO income tax", "Form MO-1040", "Missouri DOR", "RSMo § 143".
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Section 1 Metadata
| Field | Value | |---|---| | Jurisdiction | Missouri (US-MO) | | Tax type | Individual income tax | | Primary form | Form MO-1040 | | Tax year | 2025 (filed April 2026) and 2026 | | Authority | Missouri Department of Revenue | | Statute | RSMo § 143.011 et seq. | | Version | 0.1 | | Last updated | 2026-05-22 | | Validation | AI-drafted — Q3 |
Sources consulted
| # | Source | URL | |---|---|---| | 1 | Missouri DOR — Individual Income Tax Year Changes | https://dor.mo.gov/taxation/individual/tax-types/income/year-changes/ | | 2 | RSMo § 143.011 (tax rate) | https://revisor.mo.gov/main/OneSection.aspx?section=143.011 | | 3 | Missouri Form MO-1040 Instructions | https://dor.mo.gov/taxation/individual/tax-types/income/forms/ | | 4 | RSMo § 143.121 (Missouri adjusted gross income) | https://revisor.mo.gov/main/OneSection.aspx?section=143.121 |
Tax rates — TY 2025 / 2026 (all filing statuses)
| Missouri taxable income | Tax | |---|---| | $0 – $1,313 | $0 (0%) | | Over $1,313 – $2,626 | 2.0% of excess over $1,313 | | Over $2,626 – $3,939 | $26 + 2.5% of excess over $2,626 | | Over $3,939 – $5,252 | $59 + 3.0% of excess over $3,939 | | Over $5,252 – $6,565 | $98 + 3.5% of excess over $5,252 | | Over $6,565 – $7,878 | $144 + 4.0% of excess over $6,565 | | Over $7,878 – $9,191 | $197 + 4.5% of excess over $7,878 | | Over $9,191 | $256 + 4.7% of excess over $9,191 |
Standard deduction — TY 2025
| Filing status | Amount | |---|---| | Single | $15,750 | | MFJ / Qualifying Surviving Spouse | $31,500 | | MFS | $15,750 | | Head of Household | $23,625 |
Key thresholds
| Item | Value | Source | |---|---|---| | Filing deadline | April 15, 2026 (for TY 2025) | RSMo § 143.511 | | Extension | Automatic 6-month with federal extension | RSMo § 143.511 | | Estimated tax threshold | $100 expected liability | RSMo § 143.521 | | Capital gains subtraction | 100% of net capital gains (effective TY 2025) | RSMo § 143.022 |
Scope. This skill covers Missouri Form MO-1040 for full-year Missouri residents who are sole proprietors or single-member LLC owners. Missouri uses an eight-bracket graduated income tax with rates from 0% to 4.7% (TY 2025–2026). Same brackets apply to all filing statuses.
Quality tier. Q3 — AI-drafted, not independently verified. All rates and thresholds were researched on 2026-05-22 from official Missouri Department of Revenue publications. A qualified professional must review before filing.
Section 1 Metadata
| Field | Value |
|---|---|
| Jurisdiction | Missouri (US-MO) |
| Tax type | Individual income tax |
| Primary form | Form MO-1040 |
| Tax year | 2025 (filed April 2026) and 2026 |
| Authority | Missouri Department of Revenue |
| Statute | RSMo § 143.011 et seq. |
| Version | 0.1 |
| Last updated | 2026-05-22 |
| Validation | AI-drafted — Q3 |
Sources consulted
| # | Source | URL |
|---|---|---|
| 1 | Missouri DOR — Individual Income Tax Year Changes | https://dor.mo.gov/taxation/individual/tax-types/income/year-changes/ |
| 2 | RSMo § 143.011 (tax rate) | https://revisor.mo.gov/main/OneSection.aspx?section=143.011 |
| 3 | Missouri Form MO-1040 Instructions | https://dor.mo.gov/taxation/individual/tax-types/income/forms/ |
| 4 | RSMo § 143.121 (Missouri adjusted gross income) | https://revisor.mo.gov/main/OneSection.aspx?section=143.121 |
Tax rates — TY 2025 / 2026 (all filing statuses)
| Missouri taxable income | Tax |
|---|---|
| $0 – $1,313 | $0 (0%) |
| Over $1,313 – $2,626 | 2.0% of excess over $1,313 |
| Over $2,626 – $3,939 | $26 + 2.5% of excess over $2,626 |
| Over $3,939 – $5,252 | $59 + 3.0% of excess over $3,939 |
| Over $5,252 – $6,565 | $98 + 3.5% of excess over $5,252 |
| Over $6,565 – $7,878 | $144 + 4.0% of excess over $6,565 |
| Over $7,878 – $9,191 | $197 + 4.5% of excess over $7,878 |
| Over $9,191 | $256 + 4.7% of excess over $9,191 |
Missouri uses the same brackets for all filing statuses. The standard deduction varies by filing status, which determines how much income is subject to tax.
Standard deduction — TY 2025
| Filing status | Amount |
|---|---|
| Single | $15,750 |
| MFJ / Qualifying Surviving Spouse | $31,500 |
| MFS | $15,750 |
| Head of Household | $23,625 |
Missouri does NOT have a separate personal exemption. The standard deduction is the primary below-the-line deduction.
Key thresholds
| Item | Value | Source |
|---|---|---|
| Filing deadline | April 15, 2026 (for TY 2025) | RSMo § 143.511 |
| Extension | Automatic 6-month with federal extension | RSMo § 143.511 |
| Estimated tax threshold | $100 expected liability | RSMo § 143.521 |
| Capital gains subtraction | 100% of net capital gains (effective TY 2025) | RSMo § 143.022 |
City earnings taxes
| City | Rate | Notes |
|---|---|---|
| Kansas City | 1.0% | On earned income; separate return |
| St. Louis | 1.0% | On earned income; separate return |
Tier 1 rules — deterministic
| Rule ID | Rule | Source |
|---|---|---|
| MO-T1-01 | Start with federal AGI (Form 1040, Line 11) | RSMo § 143.121 |
| MO-T1-02 | Add back interest on non-Missouri state/municipal bonds | RSMo § 143.121 |
| MO-T1-03 | Subtract federal income tax paid (up to $5,000 single / $10,000 MFJ) | RSMo § 143.171 |
| MO-T1-04 | Subtract Social Security benefits included in federal AGI (fully exempt) | RSMo § 143.124 |
| MO-T1-05 | Subtract U.S. government bond interest | RSMo § 143.121 |
| MO-T1-06 | Subtract 100% of net capital gains (TY 2025+) | RSMo § 143.022 |
| MO-T1-07 | Apply standard deduction: $15,750 (single), $31,500 (MFJ), $23,625 (HoH) | RSMo § 143.131 |
| MO-T1-08 | Apply graduated rates: 0% to 4.7% across 8 brackets | RSMo § 143.011 |
| MO-T1-09 | Missouri Property Tax Credit: refundable credit for seniors/disabled (Form MO-PTC) | RSMo § 135.010 |
| MO-T1-10 | Missouri Earned Income Credit: percentage of federal EIC (non-refundable) | RSMo § 143.174 |
Tier 2 rules — requires judgment
| Rule ID | Rule | Guidance |
|---|---|---|
| MO-T2-01 | Residency determination — Missouri uses a domicile test. A person domiciled in Missouri is a full-year resident. | If taxpayer has homes in multiple states, flag for professional review. |
| MO-T2-02 | Federal tax deduction — The deduction is for federal tax actually paid (not accrued). Compute using taxes paid during the calendar year, including estimated payments and withholding. | This interacts with federal refunds/balances due in a circular manner. Use prior-year federal tax paid as a proxy. |
| MO-T2-03 | Capital gains subtraction — Applies to net long-term capital gains. Determine which gains qualify (e.g., business asset sales, stock sales). | Ensure net capital gains are correctly computed before applying 100% subtraction. |
| MO-T2-04 | Credit for taxes paid to other states (Form MO-CR) — Non-refundable credit to prevent double taxation. | Requires the other state's return. |
| MO-T2-05 | Kansas City / St. Louis earnings tax — Self-employed persons with business activity in these cities must file separately. | Flag if taxpayer operates in KC or STL. |
| MO-T2-06 | Standard vs. itemized deduction — Missouri allows either; if itemizing, Missouri generally conforms to federal Schedule A with modifications. | Compare both methods; Missouri itemized deductions may differ from federal. |
Supplier pattern library
| Pattern | Treatment | Notes |
|---|---|---|
| W-2 wages from Missouri employer | MO withholding applies; include on MO-1040 | Most common |
| Schedule C net profit (sole prop) | Flows through federal AGI → Missouri AGI | Federal tax deduction available |
| Rental income (Schedule E) | Included in federal AGI → Missouri AGI | MO-source if property in MO |
| Interest on U.S. government bonds | Subtract from Missouri AGI | RSMo § 143.121 |
| Interest on non-MO muni bonds | Add back to Missouri AGI | Taxable for MO purposes |
| Social Security benefits | Subtract from Missouri AGI (fully exempt) | RSMo § 143.124 |
| Long-term capital gains | Subtract 100% from Missouri AGI (TY 2025+) | RSMo § 143.022 |
| 1099-NEC freelance income | Flows through Schedule C → federal AGI | Estimated payments likely needed |
| Federal income tax paid | Deductible up to $5,000 (single) / $10,000 (MFJ) | RSMo § 143.171 |
Form mapping
| Missouri form / schedule | What it covers | Federal counterpart |
|---|---|---|
| Form MO-1040 | Missouri Individual Income Tax Return | Form 1040 |
| Form MO-A | Missouri Adjustments (additions/subtractions) | Schedule 1 (Form 1040) |
| Form MO-CR | Credit for Taxes Paid to Other States | N/A |
| Form MO-1040ES | Estimated Tax Payment Voucher | Form 1040-ES |
| Form MO-PTC | Property Tax Credit | N/A |
| Form MO-1040P | Part-year Resident Return | N/A |
| Form MO-NRI | Non-Resident Return | N/A |
| Schedule MO-SI | Self-Employed Tax Credit Schedule | N/A |
Refusal catalogue
| ID | Situation | Action |
|---|---|---|
| MO-R-01 | Part-year or non-resident return (MO-1040P / MO-NRI) | Refuse — out of scope |
| MO-R-02 | Corporate income tax (Form MO-1120) | Refuse — out of scope |
| MO-R-03 | Kansas City or St. Louis earnings tax return | Refuse — separate filing; out of scope |
| MO-R-04 | Multi-state income apportionment | Refuse — flag for professional review |
| MO-R-05 | Amended returns (Form MO-1040X) | Refuse — out of scope |
| MO-R-06 | Tax year other than current | Refuse — rates and thresholds may differ |
| MO-R-07 | Partnership / S-corp returns (MO-1065 / MO-1120S) | Refuse — out of scope |
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Other Missouri computations in the OpenAccountants Tax Library.
City earnings taxes
| City | Rate | Notes | |---|---|---| | Kansas City | 1.0% | On earned income; separate return | | St. Louis | 1.0% | On earned income; separate return |
Missouri AGI starting point
Missouri adjusted gross income begins with federal adjusted gross income (AGI) from federal Form 1040, Line 11, then applies Missouri-specific modifications.
Additions (Form MO-A)
Add back items Missouri does not exclude (e.g., interest on non-Missouri state/municipal bonds).
Subtractions (Form MO-A)
Subtract items Missouri excludes: 100% of net capital gains (effective TY 2025); Social Security benefits included in federal AGI; Federal income tax deduction (Missouri is one of few states that allows a deduction for federal income tax paid, capped at $5,000 single / $10,000 MFJ); U.S. government bond interest.
Missouri AGI
Federal AGI + additions − subtractions.
Standard or itemized deduction
Missouri conforms to federal amounts (with some modifications).
Missouri taxable income
Missouri AGI − deductions.
Tax
Apply the eight graduated brackets.
Credits
Apply applicable credits.
Self-employment income flow
Self-employment income flows through federal Schedule C → federal AGI → Missouri AGI. No separate Missouri schedule for self-employment income.
Federal SE tax deduction
Reflected in federal AGI; carries through to Missouri automatically.
Federal income tax deduction
Missouri allows a deduction for federal income tax paid (including SE tax), capped at $5,000 (single/HoH/MFS) or $10,000 (MFJ). This is a significant benefit.
Capital gains subtraction
100% of net capital gains reported on the federal return may be subtracted from Missouri AGI (effective TY 2025). If a sole proprietor sells business assets, the gain may qualify.
Estimated taxes
Self-employed taxpayers must make quarterly estimated payments (Form MO-1040ES) if expected liability exceeds $100. Due dates: April 15, June 15, September 15, January 15.
Health insurance deduction
Self-employed health insurance deduction is in federal AGI. No Missouri add-back.
City earnings tax
If located in Kansas City or St. Louis, self-employment earnings are subject to the 1% city earnings tax (separate filing required).
Tier 1 rules — deterministic
| Rule ID | Rule | Source | |---|---|---| | MO-T1-01 | Start with federal AGI (Form 1040, Line 11) | RSMo § 143.121 | | MO-T1-02 | Add back interest on non-Missouri state/municipal bonds | RSMo § 143.121 | | MO-T1-03 | Subtract federal income tax paid (up to $5,000 single / $10,000 MFJ) | RSMo § 143.171 | | MO-T1-04 | Subtract Social Security benefits included in federal AGI (fully exempt) | RSMo § 143.124 | | MO-T1-05 | Subtract U.S. government bond interest | RSMo § 143.121 | | MO-T1-06 | Subtract 100% of net capital gains (TY 2025+) | RSMo § 143.022 | | MO-T1-07 | Apply standard deduction: $15,750 (single), $31,500 (MFJ), $23,625 (HoH) | RSMo § 143.131 | | MO-T1-08 | Apply graduated rates: 0% to 4.7% across 8 brackets | RSMo § 143.011 | | MO-T1-09 | Missouri Property Tax Credit: refundable credit for seniors/disabled (Form MO-PTC) | RSMo § 135.010 | | MO-T1-10 | Missouri Earned Income Credit: percentage of federal EIC (non-refundable) | RSMo § 143.174 |
Tier 2 rules — requires judgment
| Rule ID | Rule | Guidance | |---|---|---| | MO-T2-01 | **Residency determination** — Missouri uses a domicile test. A person domiciled in Missouri is a full-year resident. | If taxpayer has homes in multiple states, flag for professional review. | | MO-T2-02 | **Federal tax deduction** — The deduction is for federal tax actually paid (not accrued). Compute using taxes paid during the calendar year, including estimated payments and withholding. | This interacts with federal refunds/balances due in a circular manner. Use prior-year federal tax paid as a proxy. | | MO-T2-03 | **Capital gains subtraction** — Applies to net long-term capital gains. Determine which gains qualify (e.g., business asset sales, stock sales). | Ensure net capital gains are correctly computed before applying 100% subtraction. | | MO-T2-04 | **Credit for taxes paid to other states (Form MO-CR)** — Non-refundable credit to prevent double taxation. | Requires the other state's return. | | MO-T2-05 | **Kansas City / St. Louis earnings tax** — Self-employed persons with business activity in these cities must file separately. | Flag if taxpayer operates in KC or STL. | | MO-T2-06 | **Standard vs. itemized deduction** — Missouri allows either; if itemizing, Missouri generally conforms to federal Schedule A with modifications. | Compare both methods; Missouri itemized deductions may differ from federal. |
Supplier pattern library
| Pattern | Treatment | Notes | |---|---|---| | W-2 wages from Missouri employer | MO withholding applies; include on MO-1040 | Most common | | Schedule C net profit (sole prop) | Flows through federal AGI → Missouri AGI | Federal tax deduction available | | Rental income (Schedule E) | Included in federal AGI → Missouri AGI | MO-source if property in MO | | Interest on U.S. government bonds | Subtract from Missouri AGI | RSMo § 143.121 | | Interest on non-MO muni bonds | Add back to Missouri AGI | Taxable for MO purposes | | Social Security benefits | Subtract from Missouri AGI (fully exempt) | RSMo § 143.124 | | Long-term capital gains | Subtract 100% from Missouri AGI (TY 2025+) | RSMo § 143.022 | | 1099-NEC freelance income | Flows through Schedule C → federal AGI | Estimated payments likely needed | | Federal income tax paid | Deductible up to $5,000 (single) / $10,000 (MFJ) | RSMo § 143.171 |
Form mapping
| Missouri form / schedule | What it covers | Federal counterpart | |---|---|---| | Form MO-1040 | Missouri Individual Income Tax Return | Form 1040 | | Form MO-A | Missouri Adjustments (additions/subtractions) | Schedule 1 (Form 1040) | | Form MO-CR | Credit for Taxes Paid to Other States | N/A | | Form MO-1040ES | Estimated Tax Payment Voucher | Form 1040-ES | | Form MO-PTC | Property Tax Credit | N/A | | Form MO-1040P | Part-year Resident Return | N/A | | Form MO-NRI | Non-Resident Return | N/A | | Schedule MO-SI | Self-Employed Tax Credit Schedule | N/A |
Refusal catalogue
| ID | Situation | Action | |---|---|---| | MO-R-01 | Part-year or non-resident return (MO-1040P / MO-NRI) | Refuse — out of scope | | MO-R-02 | Corporate income tax (Form MO-1120) | Refuse — out of scope | | MO-R-03 | Kansas City or St. Louis earnings tax return | Refuse — separate filing; out of scope | | MO-R-04 | Multi-state income apportionment | Refuse — flag for professional review | | MO-R-05 | Amended returns (Form MO-1040X) | Refuse — out of scope | | MO-R-06 | Tax year other than current | Refuse — rates and thresholds may differ | | MO-R-07 | Partnership / S-corp returns (MO-1065 / MO-1120S) | Refuse — out of scope |
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