Introduction
Form MO-1040 is Missouri's individual income tax return, long form. "2027 taxes" means income earned January 1 through December 31, 2027. You file that return in 2028.
There is a catch. The 2027 MO-1040 and its instructions have not been published. The latest verified edition is tax year 2025, so any 2027 line number, deduction, or bracket you see quoted today is a guess.
This guide shows the process that carries over from year to year: confirm the form applies, gather records, transfer figures, claim adjustments and credits, then check everything against the final 2027 Missouri Department of Revenue (DOR) instructions. Where it cites numbers, they are labelled by tax year.
Key Takeaways
- Use the final 2027 DOR form and instructions, not 2025 or 2026 amounts.
- Settle residency status and Missouri-source income before calculating tax.
- Reconcile federal AGI, Missouri modifications, deductions, credits, withholding, and estimated payments.
- Keep the filed return, schedules, payment confirmations, and source documents.
What Form MO-1040 Is and Who May Need It
Long form versus shorter options
MO-1040 is the long form. The tax year 2025 edition also has an MO-1040A short form, aimed at single-income situations with Missouri income only.
The short form does not fit when:
- Both spouses have income
- You have other-state income
- You claim certain adjustments or credits
- You are filing an amended return
MO-A is a schedule for adjustments and deductions, not a separate return. The old MO-1040P was eliminated starting tax year 2021. Confirm which forms the DOR offers for 2027.
Residents, part-year residents, and nonresidents
Residents report income from all sources. Nonresidents generally file when they have Missouri-source income of $600 or more, according to the Missouri DOR FAQs.
Those FAQs also list exceptions, including resident Missouri AGI under $1,200, so apply the exceptions together rather than treating any one number as universal.
Cross-border situations use two companion forms:
- MO-NRI allocates Missouri income for nonresidents and part-year residents.
- MO-CR claims a credit for tax paid to another state or jurisdiction.
Neither replaces the MO-1040. You may also need to file just to recover Missouri withholding, even if you owe nothing.
Document checklist
Before you start, collect:
- Your completed federal return (Form 1040) and schedules
- W-2s and 1099s, including 1099-R, SSA-1099, and RRB-1099
- Missouri withholding statements
- Estimated-tax payment records and any prior-year overpayment applied forward
- Records supporting deductions and credits
- Your prior Missouri return
- Any other-state returns, if you claim MO-CR
How to Complete Form MO-1040 for 2027
The steps below follow the tax year 2025 layout. Line numbers will likely shift, so treat them as a map of the logic, not a reference.
Step 1: Personal details and filing status
Enter names, Social Security numbers, address, and dependents exactly as they appear on your federal return and source documents. Use your federal filing status. Federal joint filers use Missouri married filing combined, and both spouses sign.
Step 2: Start from federal AGI
The 2025 return begins with federal adjusted gross income, not federal taxable income. Do not transfer figures until your federal return is final. A late 1099 or a federal correction will ripple through the Missouri return.
Step 3: Apply Missouri additions and subtractions
Missouri adjusts federal AGI on Schedule MO-A. In 2025, additions flow to line 2 and subtractions to line 4, producing Missouri AGI on line 5. Combined filers also split income between spouses by percentage, and those percentages must total 100%.
Step 4: Calculate taxable income
Subtract the retirement exemptions, any federal tax deduction, and your standard or itemized deduction. If you itemize federally, you may choose Missouri itemized or the Missouri standard deduction. If you took the federal standard deduction, you generally cannot itemize in Missouri. Compare both when you have a choice.
Step 5: Tax, credits, and payments
Finish the return in this order:
- Compute tax from the rate chart or worksheet.
- Apply the MO-CR credit and MO-NRI percentage if relevant.
- Enter Missouri withholding, estimated payments, and any extension payment.
- Add credits such as the Property Tax Credit and Working Family Tax Credit.
- Calculate your refund or balance due, sign, and attach required schedules.
Missouri Income, Adjustments, Deductions, and Credits
Income to review
Missouri starts from federal AGI, so the usual categories carry over: wages, self-employment, retirement income, interest, dividends, capital gains, rental income, and pass-through income. Missouri then applies its own additions and subtractions to some of those amounts.
Missouri-specific modifications (tax year 2025)
| Item | Treatment |
|---|---|
| Capital gains | Individuals may subtract 100% of income reported as a capital gain for federal purposes, for tax years beginning on or after January 1, 2025 |
| Social Security and SSD | Federally taxable benefits are deductible; Social Security requires age 62 by year-end, while SSD does not |
| Public pension | Up to $47,633 per person, reduced by taxable Social Security under the worksheet |
| Private pension | Up to $6,000 per person, subject to income limits |
| Additions | Interest on non-Missouri state and local obligations; certain nonqualified 529 or ABLE distributions |
| Other subtractions | Qualifying federal-obligation interest, state refunds, education savings contributions, military and railroad retirement income |
The DOR has also stated that the new federal deductions for tips, overtime, vehicle-loan interest, and enhanced senior amounts cannot be claimed as Missouri deductions. Verify whether that holds for 2027.
Standard and itemized deductions
Missouri ties its standard deduction to the federal amount. Published base amounts are below. They are not 2027 figures.
| Filing status | Tax year 2025 | Tax year 2026 |
|---|---|---|
| Single / married filing separately | $15,750 | $16,100 |
| Married combined / qualifying widow(er) | $31,500 | $32,200 |
| Head of household | $23,625 | $24,150 |
Itemizers use MO-A Part 2, which removes deductible state and local income taxes from the federal figure. Missouri also allows a limited federal income tax deduction: in 2025, up to $5,000 individual or $10,000 combined, phased down by AGI. It is a deduction for federal tax, not federal withholding.
Credits to verify
- Property Tax Credit: income-tested for seniors, disabled individuals, and certain surviving spouses. 2025 maximums were $1,100 (homeowners) and $750 (renters); higher statutory caps apply from 2026, with indexing from 2027.
- Working Family Tax Credit: 20% of the federal EIC for tax year 2025, nonrefundable, with no carryforward.
- MO-TC: miscellaneous credits that need a credit code and issuing-agency approval.
Confirm each credit against the final 2027 instructions before you claim it.
Using the rate chart
Missouri's top rate was 4.7% for both 2025 and 2026. Per the 2026 MO-1040ES, the 2026 schedule begins with a 0% band up to $1,348 and tops out above $9,436 at $263 plus 4.7% of the excess.
Rate reductions depend on revenue conditions, so a 2027 reduction is not guaranteed. The tax is figured on taxable income, not gross income. For 2025, the DOR example shows $3,090 of taxable income producing $38 of tax.
Filing, Payment, Refunds, and After-Submission Steps
Deadlines and extensions
For tax year 2025, filing and payment were due April 15, 2026. Confirm the 2027 date in the final instructions. Key extension rules:
- A federal extension is recognized by Missouri, and no separate MO-60 is generally needed if no additional tax is due.
- Use MO-60 to request relief or pay additional tax.
- An extension to file does not extend the time to pay.
- Late filing costs 5% per month up to 25%; late payment adds 5% of unpaid tax.
- The DOR's delinquency interest rate is 7% for calendar 2026 and 2027.
E-file or paper
You can e-file or mail a signed paper return. Do not mail a duplicate of an electronically filed return. Direct deposit is available through e-filing or the DOR fill-in return.
Payment options include:
- DOR electronic check
- Credit card
- Mailed check or money order
Track refunds with the DOR's online Return Status tool.
Attachments
Paper filers typically attach federal return pages 1-2, applicable federal schedules, Missouri withholding statements, and required Missouri schedules. MO-NRI and MO-CR have their own attachment requirements. Retain what you are not required to send.
Errors and amendments
If you find a mistake, file an MO-1040 for the affected year, mark it amended, and attach explanations and support. A federal change generally requires a Missouri amendment within 90 days.
Refund claims generally run three years from filing or two years from payment, whichever is later. Keep returns and W-2s for at least four years. The DOR can assess for six years if you omit more than 25% of Missouri AGI.
Taxpayers with complex U.S. or cross-border filings can get help from VJM Global's tax-compliance professionals, who prepare Form 1040 and 1040-NR returns. VJM Global does not have a Missouri office.
Common Mistakes to Check Before Filing
Outdated references
Do not reuse a prior-year MO-1040, standard deduction, rate chart, or deadline. Compare every figure with the final 2027 instructions.
Reconciliation errors
DOR-identified problems include:
- Missing signatures, including a spouse's
- Missing W-2s, 1099-Rs, federal pages, MO-A, MO-NRI, or MO-CR attachments
- Reporting federal or other-state withholding instead of Missouri withholding
- Omitting estimated payments or prior-year overpayments
- Wrong residency treatment
- Unsupported deductions
Final review checklist
- Names, Social Security numbers, and filing status match your federal return
- Federal AGI matches the final federal return
- Additions, subtractions, and exemptions are supported
- Standard versus itemized comparison is done
- Credits have the required schedules or certifications
- Withholding and payments match your documents
- Refund or balance-due details are correct
- Signatures and attachments are complete
- You saved submission confirmation and copies
Frequently Asked Questions
Do I need to send a copy of my federal return with my Missouri state return?
It depends on your filing method, circumstances, and Missouri schedules. Paper filers often attach federal pages 1-2 and schedules. Check the 2027 MO-1040 instructions rather than assuming.
How do I request a copy of my income tax return?
To get a copy of a filed Missouri return, submit DOR Form 1937. For federal copies, use IRS Get Transcript or Form 4506-T for transcripts, and Form 4506 for a full return copy. This is separate from filing a new return.
What is the Missouri standard deduction for 2026?
For single filers, the published 2026 base amount is $16,100. Confirm it in the official 2026 guidance, and do not use it for a 2027 return.
What is the standard deduction for 2025 in Missouri?
The 2025 base amount for single filers is $15,750. Check the official 2025 instructions for your status and any adjustments. Do not carry these figures forward to 2027.
What tax breaks are available in Missouri?
Breaks include retirement exemptions, the capital gains subtraction, itemized deductions, and credits such as the Property Tax Credit. Eligibility depends on your facts and the tax year, so verify each for 2027.
What are the income tax brackets in Missouri?
Use the official 2027 Missouri rate chart or worksheet once published. The 2025 and 2026 schedules both top out at 4.7%. Rates apply to taxable income, not gross income.
