Kentucky Form 740 is the individual income tax return that full-year Kentucky residents use to report income, apply state-specific adjustments and deductions, and reconcile what was withheld from their paychecks against what they actually owe. Kentucky taxes income at a single flat rate, so the form is less about brackets and more about getting from your federal adjusted gross income down to a Kentucky taxable figure, then applying credits.
Who Has to File Form 740
Form 740 is for people who were Kentucky residents for the entire tax year. Kentucky treats you as a resident if you were domiciled in the state on the last day of the year, or if you spent more than 183 days in Kentucky and kept a place of abode here during that time.1Kentucky Administrative Regulations. 103 KAR 17:010 Residence That second rule picks up people who keep an apartment in Kentucky while claiming another state as home.
Whether you must actually file turns on a two-chart test. Your income has to exceed the threshold in Chart A (based on family size) and the threshold in Chart B (based on filing status and age). The 2025 Chart A modified gross income thresholds are:2Department of Revenue. 2025 Kentucky Individual Income Tax Instructions for Form 740
- Family size of one: $15,650
- Family size of two: $21,150
- Family size of three: $26,650
- Family size of four or more: $32,150
If you clear Chart A, check your Kentucky adjusted gross income against Chart B:2Department of Revenue. 2025 Kentucky Individual Income Tax Instructions for Form 740
- Single, under 65: $3,270
- Single, 65 or older or blind: $4,270
- Single, 65 or older and blind: $5,270
- Married, both under 65: $3,270
- Married, one spouse 65 or older: $4,270
- Married, both 65 or older: $5,270
Both tests have to be met. Self-employment income triggers a filing requirement under the same modified gross income thresholds.
Kentucky’s Flat Tax Rate
Kentucky applies one flat rate to all taxable income. For tax year 2025, which is the return most people are filing now, the rate is 4 percent. For income earned starting January 1, 2026, the rate drops to 3.5 percent.3Kentucky Legislative Research Commission. Kentucky Revised Statutes Chapter 141 – 141.020 The statute allows further reductions if the state meets revenue benchmarks reviewed each year by the Office of State Budget Director.
How the Tax Is Calculated
Form 740 starts with the federal adjusted gross income from line 11 of your federal Form 1040, then makes Kentucky-specific modifications to produce your Kentucky adjusted gross income.2Department of Revenue. 2025 Kentucky Individual Income Tax Instructions for Form 740 Some income that’s tax-free federally gets added back; some income that’s taxable federally gets subtracted.
Additions
The most common addition is interest from bonds issued by other states or their local governments. That interest is typically exempt on your federal return, but Kentucky taxes it. If you hold Tennessee or Ohio municipal bonds, for example, that interest gets added back on your Kentucky return.
Subtractions
The biggest subtraction for retirees is Kentucky’s pension income exclusion. Up to $31,110 of qualifying retirement income from pensions, annuities, and similar distributions can be excluded from Kentucky taxable income.4Department of Revenue. Schedule P 2025 Pension Income Exclusion You claim it on Schedule P, which attaches to your Form 740. Interest from U.S. government bonds and securities is also subtracted, since Kentucky exempts it.
Standard Deduction or Itemized Deductions
After arriving at Kentucky adjusted gross income, you take either the standard deduction or itemized deductions, whichever is larger. The Kentucky standard deduction is $3,270 on 2025 returns.2Department of Revenue. 2025 Kentucky Individual Income Tax Instructions for Form 740
Kentucky’s Schedule A does not mirror the federal Schedule A. Sales tax and new motor vehicle taxes are not deductible on the Kentucky return, and personal interest like credit card interest is also disallowed. Federal itemized totals don’t carry over cleanly, so run the numbers both ways before choosing.
Credits That Reduce What You Owe
Family Size Tax Credit
If your modified gross income is at or below 100 percent of the threshold for your family size, the family size tax credit wipes out your Kentucky tax liability entirely. Between 100 and 133 percent of the threshold, you get a partial credit.5Justia. Kentucky Revised Statutes 141.066 The credit is nonrefundable, so it can zero out your tax but won’t create a refund on its own.
Child and Dependent Care Credit
Kentucky offers a nonrefundable credit equal to 20 percent of the federal child and dependent care credit you claim. If you paid for care so you could work and took the federal credit, you can claim the Kentucky version on Form 740.
If You Weren’t a Kentucky Resident All Year
Form 740 is only for full-year residents. If you moved into or out of Kentucky during the year, or lived elsewhere but earned Kentucky-source income, you file Form 740-NP instead.6Department of Revenue. 740-NP Instructions Part-year residents report Kentucky-source income from the portion of the year before (or after) they were residents, plus all income from any source during the resident portion. Full-year nonresidents report only income from Kentucky sources, including Kentucky wages, Kentucky rental income, and distributive shares from Kentucky businesses.
Kentucky has reciprocal tax agreements with Illinois, Indiana, Michigan, Ohio, Virginia, West Virginia, and Wisconsin.7Department of Revenue. 103 KAR 17:140 Individual Income Tax – Reciprocity If you live in one of those states and commute into Kentucky to work, your wages and salaries are exempt from Kentucky income tax; you file only with your home state. The exemption covers wages and salaries only. Other Kentucky-source income, like rental income or business profits, may still require a Kentucky nonresident return. And if you’re domiciled in a reciprocal state but spend more than 183 days in Kentucky with a place of abode here, reciprocity falls away and Kentucky treats you as a resident.
What to Gather Before You Start
- Social Security numbers for yourself, your spouse if filing jointly, and any dependents
- Your federal Form 1040, since Kentucky starts from the federal adjusted gross income on line 11
- W-2s and 1099s showing Kentucky state tax withheld
- Records of any quarterly estimated tax payments you made to the Department of Revenue
- Pension or retirement income documentation if you plan to claim the Schedule P exclusion
Download the form and instructions for the specific tax year you’re filing. Using an older form is a common cause of processing delays.
How to File
The Kentucky Department of Revenue runs KY File, a free online system that lets you complete and submit the return electronically.8Department of Revenue. Free Electronic Filing It does basic math and field validation, which reduces errors. Third-party tax software can also transmit the Kentucky return. Electronically filed returns are typically processed in four to six weeks.9Department of Revenue. KY File FAQs
If you file on paper, the mailing address depends on whether you owe:
- Refund or no payment due: Kentucky Department of Revenue, Frankfort, KY 40618-0006
- Payment enclosed: Kentucky Department of Revenue, Frankfort, KY 40619-0008
Paper returns take 10 to 14 weeks to process.9Department of Revenue. KY File FAQs If you’re expecting a refund, filing electronically pays off.
Deadline and Extensions
Form 740 is due April 15, the same date as your federal return. If April 15 falls on a weekend or holiday, the deadline shifts to the next business day.10Department of Revenue. April 2026
Need more time? File Form 740EXT to request a six-month extension, pushing the filing deadline to October 15.11Department of Revenue. 740EXT Application for Extension of Time to File The extension gives you more time to file, not more time to pay. If you owe, you need to estimate the amount and pay it by April 15, or penalties and interest start running even though the return itself isn’t due.
Penalties and Interest
Late filing carries a penalty of 2 percent of the tax due for each 30-day period (or fraction) the return is late, capped at 20 percent.12Department of Revenue. Penalties, Interest and Fees Late payment carries the same 2 percent per 30 days, also capped at 20 percent. The two run at the same time, so filing late and paying late can cost up to 40 percent of the tax owed in penalties.
If you never file and the Department of Revenue assesses the tax itself, the penalty is 5 percent per 30 days, capped at 50 percent, with a minimum of $100. Interest also accrues on any unpaid balance at 9 percent for 2026, running from the original due date until the balance is paid. An extension does not stop interest.