What Is Kentucky State Income Tax? Rates, Credits, and Filing

Kentucky state income tax is a flat 3.5% of net income for the 2026 tax year, applied to residents on all income and to nonresidents on income earned from Kentucky sources.¹ The rate is the same for every filer regardless of income level or filing status, but what you actually pay depends on your residency, your deductions, and a handful of credits that can shrink the bill or wipe it out entirely.

The Current Rate and What’s Coming

For 2026, you multiply your Kentucky net income by 0.035. That’s it for the rate calculation. The flat rate has stepped down over the past few years: 4.5% for 2023, 4% for 2024 and 2025, and 3.5% for 2026.²

Starting with the 2027 tax year, Kentucky is scheduled to move off the single flat rate. The enacted legislation creates graduated brackets for higher earners: 3.5% on the first $250,000 of net income, 6% on income between $250,000 and $300,000, and a flat 6% on all net income if total earnings exceed $300,000.¹ For the return you’ll file next spring covering 2026, none of that applies yet.

Do You Have to File a Kentucky Return?

Kentucky uses a two-part income test. You must file if your modified gross income exceeds a threshold tied to your family size, and your Kentucky adjusted gross income exceeds a second, lower threshold tied to filing status.³

The 2025 modified gross income thresholds the Department of Revenue currently publishes are:

Family of one: $15,650
Family of two: $21,150
Family of three: $26,650
Family of four or more: $32,150

If you clear the modified gross income threshold, you then check the Kentucky adjusted gross income threshold. For a single filer under 65, that’s $3,270; for a single filer 65 or older, $4,270. Married couples filing jointly follow the same pattern, with the figure rising when one or both spouses are 65 or older.³ These figures are adjusted annually and are expected to rise slightly for 2026 in line with the higher standard deduction.

Self-employed filers get no shortcut. If your gross receipts exceed the modified gross income threshold for your family size, you have to file regardless of what your Kentucky adjusted gross income looks like.⁴

Which Income Kentucky Can Tax

Your residency category decides this. Kentucky recognizes three: full-year resident, part-year resident, and nonresident.⁵

Full-year residents owe tax on all income from every source, whether earned in Kentucky, another state, or abroad.² Even if your permanent home is somewhere else, Kentucky treats you as a resident when you spend more than 183 days in the Commonwealth during the year and keep a place to live there.⁵

Part-year residents prorate: they report the income earned while living in Kentucky plus any Kentucky-source income earned during the nonresident portion of the year. Nonresidents owe Kentucky tax only on income from tangible property in the state, intangible property with a business connection to Kentucky, or work performed within the state’s borders.²

Military members keep the domicile they held when they entered service. If you were a Kentucky resident when you were inducted, you remain liable on all income no matter where you’re stationed.⁵

If You Commute From a Neighboring State

Kentucky has reciprocal agreements with Illinois, Indiana, Michigan, Ohio, Virginia, West Virginia, and Wisconsin.⁵ If you live in one of those states and work in Kentucky, your wages and salaries are generally exempt from Kentucky income tax. Virginia’s agreement only covers residents who commute daily to a Kentucky workplace, and Ohio’s excludes S corporation shareholder-employees who own 20% or more of the company.⁶

To stop your employer from withholding Kentucky tax, give them Form 42A809 (Certificate of Nonresidence). They’ll keep it on file and stop the withholding.⁷ Skip that step and you’ll have to file a Kentucky nonresident return to recover what was over-withheld. Reciprocity also disappears if you keep a place to live in Kentucky and spend more than 183 days there.⁶

Deductions and Exclusions That Lower Your Taxable Income

Kentucky starts with your federal adjusted gross income and applies state-specific add-backs and subtractions to reach your Kentucky net income.⁸ A common add-back is interest from bonds issued by other states. The subtractions are where most filers find real savings.

The Standard Deduction

The Kentucky standard deduction for 2026 is $3,360, up $90 from $3,270 the prior year.⁹ It’s recalculated each year under KRS 141.081 for inflation. You can itemize instead if your allowable itemized deductions add up to more.⁸ Because Kentucky’s standard deduction is much smaller than the federal one, the itemize-or-not math sometimes comes out differently at the state level.

Retirement Income

You can exclude up to $31,110 of retirement income for 2026, covering pensions, annuities, and distributions from retirement accounts.⁸ Federal, Commonwealth, and Kentucky local government retirees with service before January 1, 1998 may qualify for a larger exclusion calculated on Schedule P.

Active Duty Military Pay

Active duty military pay is fully exempt from Kentucky income tax. If that’s your only income, you don’t have to file at all unless Kentucky tax was withheld and you want it refunded.¹⁰ The exemption covers all branches, the National Guard, and reserve components while on active duty.

Credits That Reduce the Tax Itself

Credits come off your tax bill after it’s calculated, dollar for dollar.

Family Size Tax Credit

This is where lower-income filers see the biggest benefit. It’s a sliding-scale credit tied to modified gross income and household size, benchmarked against federal poverty guidelines. The 2025 reference thresholds are $15,650 for a family of one, $21,150 for two, $26,650 for three, and $32,150 for four or more. You may qualify if your total modified gross income is $42,760 or less.⁴ The percentage drops as income rises and phases out entirely at the top. At the lowest income levels, this credit can eliminate what you owe.

Personal Tax Credit

Narrower than the name suggests. Only three groups qualify: people 65 or older, people who are legally blind, and Kentucky National Guard members. The credit is $40 per qualifying person for age and $40 for blindness, so someone who is both 65 and blind can claim $80. National Guard members get $20; reserve members outside the Kentucky National Guard don’t qualify.¹¹ Report them on Schedule ITC with your Form 740 or 740-NP.⁸

Child and Dependent Care Credit

Kentucky’s version is 20% of the federal credit you claimed under IRC Section 21.⁴ A $1,000 federal credit becomes a $200 Kentucky credit. Claim it directly on Form 740 or 740-NP.

Filing: Forms, Deadline, and Extensions

Full-year residents file Form 740. Nonresidents and part-year residents file Form 740-NP.⁸ The state offers KY File, a free electronic filing portal at filetaxes.ky.gov that works like a digital version of the paper forms. It handles basic math and error checks but doesn’t walk you through tax situations the way commercial software does, so finish your federal return first.¹² Paper returns are also accepted at the address in the form instructions.

The deadline is April 15. Two ways to extend it: if the IRS has already granted you a federal extension, Kentucky automatically grants the same extension (just attach a copy of your federal extension to the Kentucky return when you file). Or file Form 740EXT with the state for a six-month extension, twelve months if you’re outside the United States. An extension to file is not an extension to pay. If you owe, send payment by April 15 to avoid penalties and interest.¹³

Penalties and Interest for Missing the Deadline

Kentucky treats late filing and late payment as separate problems with separate penalties.

The late filing penalty is 2% of the total tax due for every 30 days (or any part of 30 days) the return is late, capped at 20%. If you never file and the Department of Revenue has to assess the tax itself, the failure-to-file penalty jumps to 5% per 30-day period, capped at 50%, with a minimum of $100.¹⁴

The late payment penalty mirrors late filing: 2% of unpaid tax per 30-day period, capped at 20%. On top of any penalty, interest accrues at an annual rate set each year; for 2026 that rate is 9%, running from the original due date until the balance is paid.¹⁴ Penalties and interest stack, so filing late and paying late means both sets of charges at once. Filing on time with a partial payment is always better than not filing.

A Note on Local Occupational Taxes

If you see a separate local tax line on your pay stub that doesn’t match anything on your state return, that’s because many Kentucky cities and counties impose their own occupational license taxes on wages and net business profits. These are collected by local governments, not the Department of Revenue, and are governed by local ordinances rather than state statutes.¹⁵ Employees usually have them withheld automatically; the self-employed have to report and pay directly to the city or county where they work. Rates vary by jurisdiction, and local non-compliance brings its own penalties separate from anything the state imposes.

1
Kentucky Legislative Research Commission. Kentucky House Bill 13 – An Act Relating to the Individual Income Tax Rate
2
Justia. Kentucky Revised Statutes 141.020 – Levy of Income Tax on Individuals
3
Kentucky Department of Revenue. Do I Need to File a Return
4
Department of Revenue. 740 Packet Instructions 2025
5
Kentucky Legislative Research Commission. 103 KAR 17:010 – Residence
6
Kentucky Legislative Research Commission. 103 KAR 17:140 – Individual Income Tax – Reciprocity – Nonresidents
7
Commonwealth of Kentucky, Department of Revenue. 42A809 Certificate of Nonresidence
8
Kentucky Department of Revenue. Individual Income Tax
9
Department of Revenue. Kentucky DOR Announces 2026 Standard Deduction
10
Department of Revenue. Military Exemptions
11
Kentucky Department of Revenue. Tax Credits
12
Department of Revenue. Kentucky Income Tax Return Nonresident or Part-Year Resident Instructions for Form 740-NP
13
Cornell Law School – Legal Information Institute. 103 KAR 15:050 – Filing Dates and Extensions
14
Department of Revenue. Penalties, Interest and Fees
15
Kentucky Legislative Research Commission. Kentucky Revised Statutes 68.180 – Occupational License Tax in Counties Containing 300,000 Population