If you live outside Kentucky but earned income from Kentucky sources during the year, you generally have to file a Kentucky nonresident return on Form 740-NP, and the Kentucky nonresident filing requirements apply no matter how small the amount. The state taxes that Kentucky-source income at a flat 3.5% for tax year 2026, down from 4% for tax year 2025.1Kentucky Department of Revenue. 2026 Kentucky Withholding Tax Formula A narrow set of nonresidents skip the full return under reciprocal agreements or military spouse protections, and those exceptions are worth checking before you file anything.
Who Has to File
A full-year nonresident who had any income from Kentucky sources must file Form 740-NP, the Kentucky Nonresident or Part-Year Resident Income Tax Return.2Kentucky Department of Revenue. 2025 Kentucky Individual Income Tax Forms There is no dollar threshold that excuses filing. Even a small amount of Kentucky wages, or Kentucky tax your employer already withheld, still triggers a return.3Kentucky Department of Revenue. Individual Income Tax
Part-year residents use the same form. If you moved into or out of Kentucky during the year, Form 740-NP is where you report income earned while living in the state and any Kentucky-source income earned while you were a nonresident.4Kentucky Department of Revenue. 2025 Kentucky Income Tax Return Nonresident or Part-Year Resident Instructions
What Kentucky Can Tax
Kentucky reaches three broad categories of nonresident income: pay for services performed in the state, income from property located in the state, and distributive shares from pass-through entities doing business in the state.5Legal Information Institute. 103 KAR 17:060 – Income Subject to Taxation; Portions The statute also covers income from any business, trade, profession, or occupation carried on in Kentucky.6Kentucky Legislative Research Commission. KRS 141.020 – Tax on Income
In practice, that means wages for work physically performed in Kentucky, rent from Kentucky real estate, gains from selling Kentucky property, and profits from a business operating in the state. If you are a partner, member, or shareholder in a pass-through entity doing business in Kentucky, your share of that entity’s income is Kentucky-source regardless of where you live, and the entity is required to withhold Kentucky tax on your share before distributing it.7Kentucky Department of Revenue. Nonresident Withholding Tax
Dividends, interest, and capital gains from stock sales are generally not Kentucky-source income for a nonresident. The statute places the situs of intangible personal property at the residence of the owner.6Kentucky Legislative Research Commission. KRS 141.020 – Tax on Income The exception is intangible property that has acquired a business situs in Kentucky by being used in a trade or business operating in the state.
Reciprocal Agreements Change the Answer for Some Wage Earners
Kentucky has reciprocal tax agreements with seven states. The covered categories are not identical, so the details of your state’s agreement matter:8Legal Information Institute. 103 KAR 17:140 – Individual Income Tax – Reciprocity – Nonresidents
- Illinois: wages and salaries
- Indiana: wages, salaries, and commissions
- Michigan: income from personal services, including wages and salaries
- Ohio: wages and salaries, except wages an S corporation pays to a shareholder-employee who owns 20% or more of the company
- Virginia: salaries and wages, only for residents who commute daily into Kentucky
- West Virginia: wages and salaries
- Wisconsin: income from personal services, including wages and salaries
If you live in one of these states and your only Kentucky income falls within the covered category, that income is exempt from Kentucky tax. To recover Kentucky tax your employer withheld, file Form 740-NP-R, the Nonresident Reciprocal State Income Tax Return.9Kentucky Department of Revenue. Kentucky Form 740-NP-R Nonresident Reciprocal State Income Tax Return To stop the withholding going forward, give your employer a completed Form K-4.
The edges of these agreements catch people. A Virginia resident who works remotely and drives to a Kentucky office now and then does not qualify under Virginia’s agreement, which is limited to daily commuters. An Ohio resident who owns 20% or more of a Kentucky S corporation cannot use the agreement for salary from that company. And if you have any Kentucky-source income the agreement does not cover, such as rental income or self-employment earnings, you still owe a Form 740-NP for the non-exempt portion.
Military Spouses
Under the Military Spouses Residency Relief Act, a military spouse’s Kentucky income is not taxable when three conditions are met: the servicemember is stationed in Kentucky under military orders, the spouse is in Kentucky solely to be with the servicemember, and both claim legal residence in the same state other than Kentucky.10Kentucky Department of Revenue. Military Spouse Income Tax Relief The spouse can claim the servicemember’s home state even without having lived there.
Qualifying spouses should file a new Form K-4 with their employer to stop Kentucky withholding. If Kentucky tax was already withheld, file Form 740-NP and check the Military Spouse box to request a refund.10Kentucky Department of Revenue. Military Spouse Income Tax Relief
How the Tax Is Calculated
Form 740-NP uses apportionment so you only pay Kentucky on the Kentucky portion of your income. You report your total federal income and your Kentucky-source income, and the form calculates the ratio between them.4Kentucky Department of Revenue. 2025 Kentucky Income Tax Return Nonresident or Part-Year Resident Instructions That ratio prorates your deductions: if 30% of your income came from Kentucky, you claim 30% of your adjustments on the Kentucky return.
After prorated deductions, you multiply Kentucky taxable income by the flat rate. That is 3.5% for tax year 2026 and 4% for tax year 2025 returns filed in 2026.1Kentucky Department of Revenue. 2026 Kentucky Withholding Tax Formula4Kentucky Department of Revenue. 2025 Kentucky Income Tax Return Nonresident or Part-Year Resident Instructions
Family Size Tax Credit
Lower-income nonresidents may qualify for the Family Size Tax Credit, which can reduce or eliminate Kentucky tax. The credit phases out as modified gross income rises above a threshold tied to the federal poverty level. For tax year 2025, the full 100% credit begins at $15,650 for a single filer, $21,150 for a family of two, $26,650 for a family of three, and $32,150 for a family of four or more.11Kentucky Department of Revenue. Family Size Tax Credit Table TY2025 The credit decreases at higher incomes, drops to 10% of tax, and phases out entirely around 133% of the threshold.
Credit From Your Home State
Kentucky does not give nonresidents a credit for taxes paid to their home state. The credit runs the other way: you pay Kentucky on the Kentucky-source income, and your home state typically credits you for the Kentucky tax you paid.3Kentucky Department of Revenue. Individual Income Tax A properly completed Form 740-NP is what establishes the credit amount your home state will allow. The specific rules for claiming it depend on your resident state.
Estimated Payments When Nothing Is Withheld
If you expect to owe $500 or more in Kentucky tax after withholding and refundable credits, you likely need to make quarterly estimated payments.12Kentucky Department of Revenue. Instructions for Filing Estimated Tax Vouchers This tends to hit nonresidents with Kentucky rental income, self-employment income, or pass-through distributions where no Kentucky tax is being withheld at the source.
Estimated tax is generally required if you expect to owe at least $500 and your withholding plus refundable credits will cover less than the smaller of 90% of the current year’s tax or 100% of the prior year’s tax. If your Kentucky adjusted gross income for the prior year exceeded $150,000 ($75,000 if married filing separately), the 100% safe harbor rises to 110%.12Kentucky Department of Revenue. Instructions for Filing Estimated Tax Vouchers
For calendar-year filers, quarterly payments are due April 15, June 15, and September 15 of the tax year, and January 15 of the following year. Pay by mailing Form 740-ES with a check or through the Department of Revenue’s online portal.
Filing Deadline and Extensions
Kentucky follows the federal calendar. For tax year 2025, returns are due April 15, 2026. Kentucky does not require a separate extension request. A federal extension (Form 4868) automatically extends your Kentucky filing deadline by six months, and you attach a copy of the federal extension to your Kentucky return when you file.13Kentucky Department of Revenue. Kentucky Form 40A102 – Application for Extension of Time to File
An extension only extends the time to file. It does not extend the time to pay. Interest and penalties on any unpaid balance start running from the original April deadline even with a valid extension in place.
How to File and Pay
You can file Form 740-NP electronically through approved tax software that supports Kentucky e-file. Kentucky also offers KY File, a free online tool for completing and submitting the return directly through the Department of Revenue.14Kentucky Department of Revenue. Free Electronic Filing Paper returns go to:
Kentucky Department of Revenue
Frankfort, KY 40618-000615Kentucky Department of Revenue. Filing Tips
Electronically filed returns are generally processed within four to six weeks; paper returns typically take eight to twelve.15Kentucky Department of Revenue. Filing Tips16Kentucky Department of Revenue. DOR Begins Processing Refunds Earlier Than Originally Expected
Pay online through the Department of Revenue’s payment portal, or mail a check or money order payable to Kentucky State Treasurer to:
Kentucky Department of Revenue
Frankfort, KY 40620-002117Kentucky Department of Revenue. E-file and Payment Options
The payment address is different from the return address, so watch that when mailing.
Late Filing and Late Payment
Kentucky charges separate penalties for filing late and paying late, and they stack. Each is 2% of the tax due per 30-day period (or fraction of a period), capped at 20%, with a $10 minimum.18Kentucky Department of Revenue. Penalties, Interest and Fees Interest also accrues on any unpaid balance from the original due date. For the 2026 calendar year, Kentucky’s rate on unpaid tax is 9% annually.19Kentucky Department of Revenue. Tax Interest Rate Update for 01-01-26 Even if you plan to extend the return, paying what you estimate you owe by April keeps these charges from starting.