Kansas and Missouri do not have a tax reciprocity agreement. If you live in one state and work in the other, you file two state income tax returns every year: a nonresident return in your work state and a resident return in your home state. A credit on the resident return keeps the same wages from being taxed twice in full, but it does not erase the paperwork, and depending on which direction you commute, you can still owe a balance to your home state in April.
How Each State Taxes Your Wages
State income tax follows a source rule. The state where you physically perform the work gets first claim on that income, no matter where you live. A Kansas resident who drives into Missouri for work owes Missouri tax on those earnings. A Missouri resident commuting to Kansas owes Kansas tax on that income. The work state taxes first; the home state taxes later and gives credit.
That first obligation means a nonresident return in the work state. A Kansas resident earning wages in Missouri files Missouri Form MO-1040 with the MO-NRI schedule, which prorates Missouri tax to only the income earned inside Missouri.1Missouri Department of Revenue. Nonresidents and Residents with Other State Income A Missouri resident earning wages in Kansas files Kansas Form K-40, checks the nonresident box, and calculates Kansas tax only on the Kansas-sourced portion.2Kansas Department of Revenue. Kansas Individual Income Tax Form K-40 Both calculations start from federal adjusted gross income and apply a ratio of in-state income to total income. Your filing status on each state return must match your federal Form 1040, and you should attach W-2s and anything else that documents where the income was earned.
The filing thresholds are low. Kansas requires a nonresident return for any income from Kansas sources, with no dollar minimum.3Kansas Department of Revenue. Frequently Asked Questions About Individual Income Missouri’s trigger is $600 of Missouri-source income. A short project across the state line can be enough to pull you in, so track your work days.
The Credit for Taxes Paid to the Other State
After the nonresident return, you file a resident return in your home state covering all of your income from every source. To prevent the same wages from being taxed twice in full, your home state grants a credit for the income tax you already paid to the work state.
Missouri residents claim it on Form MO-CR, attached to Form MO-1040.1Missouri Department of Revenue. Nonresidents and Residents with Other State Income Kansas residents compute it using a worksheet in the K-40 instructions and enter the result on Form K-40. Both states require a complete copy of the nonresident return as an attachment.
The credit is not a full refund of whatever you paid. It is capped at the lesser of two numbers: the actual tax paid to the work state, or the tax your home state would have charged on that same income. You end up paying the higher of the two state rates on your cross-border wages, never both rates in full.
In practice this breaks differently depending on direction. Missouri’s top rate for 2026 is approximately 4.7%; Kansas’s top rate reaches 5.58%. A Kansas resident working in Missouri pays Missouri’s 4.7% first, then takes the credit against Kansas. Because Kansas’s rate is higher, the credit absorbs the Missouri payment but leaves a residual balance to Kansas roughly equal to the rate difference. A Missouri resident working in Kansas pays the higher Kansas rate first, but the Missouri credit is capped at Missouri’s lower rate, so the extra Kansas tax is a real cost rather than something recoverable at home.
The credit applies only to wages properly sourced to the other state. Interest, dividends, and rental income from property in your home state are taxed only by the resident state and stay out of the credit calculation.
Withholding and Estimated Payments
Your employer withholds state income tax for the state where you physically work, using a state-specific form rather than the federal W-4. Kansas employers use Form K-4; Missouri employers use Form MO W-4.4Kansas Department of Revenue. Kansas Withholding Allowance Certificate K-4 If you recently changed jobs or started commuting across the line, check your pay stub to confirm the right state is being withheld.
Employers typically do not withhold anything for your home state. The credit covers most of your home-state liability, but when the home-state rate is higher than the work-state rate, the gap shows up as a balance due. Kansas residents working in Missouri are the group most likely to see this, because Kansas rates run higher than Missouri’s.
Once the expected balance crosses a threshold, you have to make quarterly estimated payments. Kansas requires them when expected tax after withholding and credits is $500 or more.5Kansas Department of Revenue. Kansas 2026 Individual Estimated Tax K-40ES Missouri’s threshold is $100.6Missouri Department of Revenue. 2026 Declaration of Estimated Tax for Individuals MO-1040ES Kansas residents use Form K-40ES; Missouri residents use Form MO-1040ES. Payments are due April 15, June 15, September 15, and January 15 of the following year.7Internal Revenue Service. Individuals 2
Deadlines and Extensions
Both Kansas and Missouri individual returns are due April 15, so you have two deadlines on the same day. Prepare the nonresident return first; the tax figure from it drives the credit on your resident return.
Each state offers a six-month extension to October 15. Kansas grants its extension automatically if you have an approved federal extension on IRS Form 4868; include a copy with your Kansas return. Missouri does the same when you have a federal extension and either expect a refund or do not expect to owe more Missouri tax, in which case Form MO-60 is not needed. If you do expect to owe Missouri, file Form MO-60 with payment by April 15.8Missouri Department of Revenue. Form MO-60 Application for Extension of Time to File An extension moves the filing date, not the payment date. Unpaid tax after April accrues interest in both states.
Penalties
Kansas charges a late-payment penalty of 1% per month on the unpaid balance, capped at 24%, with interest running separately at 8% annually for 2026.9Kansas Department of Revenue. Penalty and Interest Missouri adds 5% of the unpaid amount plus interest if tax is not paid by the original due date.8Missouri Department of Revenue. Form MO-60 Application for Extension of Time to File
Underpayment of estimated taxes carries its own charge. Missouri uses Form MO-2210 to calculate interest on each quarterly shortfall between the installment due date and the date you actually paid; for 2024 returns the underpayment rate ran 8% to 9%, and no penalty applied if the total underpayment was under $500.10Missouri Department of Revenue. Underpayment of Estimated Tax by Individuals Form MO-2210 You can generally avoid the underpayment penalty in either state by paying through withholding and estimated payments at least 90% of your current-year liability or 100% of your prior-year tax.
The Kansas City Earnings Tax
Commuters in the Kansas City metro face an added 1% municipal tax on earned income. It applies to anyone who lives in or works within Kansas City, Missouri, city limits.11City of Kansas City. Have You Paid Your KCMO Earnings Tax E-Tax Residents owe the 1% on all earned income regardless of work location. Nonresidents owe it only on income earned inside the city.12City of Kansas City. Tax FAQs
Most employers withhold the 1% automatically, and in that case no separate filing is required. If the tax is not fully withheld, Form RD-109 reports and pays the balance. Nonresidents with days worked outside the city can file Form RD-109NR to request a refund proportionate to those outside days, verified by the employer.13City of Kansas City. City Tax Forms
Because the earnings tax is a local tax rather than a state tax, Missouri does not credit it on the state return. Kansas does something more helpful for its residents: the Kansas Department of Revenue allows residents to include local income and earnings taxes paid to another state’s jurisdictions when computing the credit for taxes paid to that state.14Kansas Department of Revenue. Notice 15-15 Credit for Taxes Paid to Another State A Kansas resident working in Kansas City, Missouri, can combine Missouri state tax and the 1% earnings tax on the K-40 credit worksheet. The combined credit still cannot exceed what Kansas would have charged on that income, but because Kansas rates are higher, most of the earnings tax tends to be absorbed. A Missouri resident who lives inside Kansas City pays the earnings tax as a resident, with no offsetting credit on the Missouri return.
Remote and Hybrid Work
The source rule is simple when you commute to an office every day. It becomes more involved when some of your workweek happens at home. Income is sourced to where you physically perform the work, so days you work from home shift that portion of income back to your resident state. If you split your time, each state taxes the share of wages tied to days worked within its borders.
That makes a work-location log worth keeping. If your employer withholds 100% of your wages for the work state while you spend significant days working from home, you can end up over-withheld in the work state and under-withheld at home. Adjusting withholding or adding estimated payments during the year prevents a surprise in April.
For hybrid workers inside Kansas City, Form RD-109NR allows a refund of the earnings tax for days worked outside city limits, provided the employer verifies the day count.13City of Kansas City. City Tax Forms For a Kansas resident who teleworks part of the week rather than commuting in every day, a clean record of work locations is one of the simpler ways to reduce the overall bill.