Kentucky K-4 & W-4 Withholding Calculator 2026

Kentucky does not use your federal W-4 to set state withholding, but it also does not ask you to count allowances. Every wage earner is taxed at a flat 3.5% for 2026, with a standard deduction of $3,360, and there are no personal exemptions. Your employer applies the same formula to everyone.

That means most Kentucky employees never file a K-4. The Department of Revenue says Form K-4 (Kentucky's Withholding Certificate) is needed only to document an exemption from withholding or to ask for additional withholding on top of the formula amount.

Employers annualize your pay, subtract the $3,360 standard deduction, multiply by 3.5%, and divide by your pay periods. For example, a $50,000 salary works out to ($50,000 − $3,360) × 3.5% = about $1,632 a year, or about $62.78 per biweekly paycheck.

Because the formula is a flat percentage, Kentucky withholding tends to be close to your actual state tax for a single job. If you have two jobs, each employer applies the deduction separately, so the second job can under-withhold slightly.

You may check box 1 if you had a right to a refund of all Kentucky income tax withheld last year because you had no Kentucky tax liability, and you expect a refund of all of it this year. The Department of Revenue gives income thresholds based on family size; if your income is below them you may have no Kentucky liability. A 2026 exemption expires February 15, 2027.

Three other boxes cover special cases: a Fort Campbell exemption for nonresidents who work only at that base, a nonresident military spouse exemption, and residents of reciprocal states who work in Kentucky. In every case you must file the K-4 with your employer before they will stop withholding.

Kentucky has reciprocal agreements with Illinois, Indiana, Michigan, West Virginia, Wisconsin, Virginia (if you commute daily), and Ohio (if you are not a shareholder-employee holding 20% or more of an S corporation). If you live in one of those states and work in Kentucky, you can check box 4 on the K-4 and Kentucky will not withhold. Your home state taxes the wages instead.

Kentucky residents who work in another state have the reverse situation: check that state's rules and make sure your Kentucky return gets the credit you are entitled to.

Many Kentucky cities and counties also charge an occupational license tax on wages, which your employer withholds separately from the state tax. The calculator estimates state income tax only; check with your city or county for local rates.

Your federal W-4 is a separate form and controls federal withholding. If you owe at tax time, see our guide on how to stop owing taxes, and use the federal calculator for Steps 2 to 4.