Kentucky Form K-4 (2026): Withholding Certificate

What is Kentucky Form K-4?

Kentucky taxes all wage earners at a flat 3.5% rate with a standard deduction allowance, so unlike many state certificates the K-4 has no allowances to count. The 2026 form (42A804, 12-2025) is only needed when you want to claim one of four exemptions from Kentucky withholding, or when you want additional tax withheld under an agreement with your employer.

The four exemptions are: no Kentucky income tax liability expected this year; the Fort Campbell exemption for nonresidents who work only at Fort Campbell; the nonresident military spouse exemption; and living in a reciprocal state while working in Kentucky. The military spouse and reciprocal state exemptions each come with a short worksheet on page 2.

VergeHR walks you through the form, fills in both worksheets, checks that the military spouse questions are all answered YES before you claim that exemption, and prints everything into the Department of Revenue's own PDF. VergeHR never submits it: you give the K-4 to your employer.

Who fills it: The employee.
Given to: Your employer, who keeps a copy.
Tax rate on the form: A flat 3.5%, with a standard deduction allowance of $3,360.
Exemptions: No liability expected; Fort Campbell; nonresident military spouse; reciprocal state.
Box 1 expiry: The 2026 no-liability exemption expires February 15, 2027.
Cost: Free to fill out on any VergeHR account.

Who needs to fill out Kentucky Form K-4?

Employees who had no Kentucky income tax liability last year and expect none this year.
Nonresidents of Kentucky who earn wages only as employees at Fort Campbell.
Nonresident spouses of military servicemembers stationed in Kentucky.
People who live in Illinois, Indiana, Michigan, West Virginia, Wisconsin, Virginia (commuting daily) or Ohio (with an S corporation condition) and work in Kentucky.
Anyone who wants additional Kentucky tax withheld from each paycheck.

When to Use Kentucky Form K-4

When you start a job in Kentucky and qualify for an exemption. Withholding stops only after you file the K-4 with your employer.
Each year for the no-liability exemption, which expires on February 15 of the following year.
Within 10 days of moving to Kentucky, to revoke a Fort Campbell exemption.
When any military spouse worksheet answer changes to NO, which ends that exemption.
Whenever you want to start or change additional withholding.

What You Need Before You Start

Your Social Security number, full name and mailing address.
For box 1: your last-year and expected modified gross income compared with the thresholds printed on the form.
For box 2: your state of residence.
For box 3: your spouse's military status and state of domicile, and a copy of your spouse's military picture ID issued by the U.S. Department of Defense for your employer.
For box 4: the reciprocal state you live in.

What’s On Kentucky Form K-4

The 2026 edition has 2 pages. VergeHR asks for it in 6 parts, and it is signed by Employee:

Your detailsEmployee
Check if exemptEmployee
Military spouse worksheet (box 3)Employee
Reciprocal state worksheet (box 4)Employee
Additional withholdingEmployee
SignatureEmployee

How to fill out Kentucky Form K-4, step by step

1 Your details

Enter your Social Security number, your name (last, first, middle initial) and your mailing address. VergeHR prints the name in the order the form asks for.

2 Box 1: no liability expected

You may tick box 1 if, for 2025, you had a right to a refund of all Kentucky tax withheld because you had no liability, and for 2026 you expect a refund of all of it. The form lists the 2025 thresholds based on the federal poverty level: $15,650 for a family of one, $21,150 for two, $26,650 for three and $32,150 for four or more, compared with your modified gross income.

3 Box 2: Fort Campbell

Pay earned at the Fort Campbell, Kentucky, military base is exempt from Kentucky income tax for nonresidents. Tick box 2 only if you are not a Kentucky resident and earn wages only as an employee at Fort Campbell, and enter your state of residence.

4 Box 3: nonresident military spouse

Answer the six worksheet statements on page 2: your spouse is a servicemember, you are not, your spouse has orders to a Kentucky location, you live at the same address, your spouse's domicile is another state that you elect to use (with its two-letter code), and you are in Kentucky solely to be with your spouse. Only if every answer is YES are you exempt.

5 Box 4: reciprocal state

If you have not been a Kentucky resident during the year and live in Illinois, Indiana, Michigan, West Virginia or Wisconsin, or in Virginia and commute daily, or in Ohio and are not a 20%-or-greater S corporation shareholder-employee, tick box 4 and mark your state on page 2.

6 Additional withholding and signature

Enter any additional amount to withhold per pay period under agreement with your employer, then sign and date the certificate.

Common Mistakes to Avoid

Ticking box 3 when one of the six military spouse statements is NO.
Claiming the Virginia reciprocal exemption without commuting daily, which the form says is required.
Keeping a Fort Campbell exemption after moving to Kentucky; it must be revoked within 10 days.
Forgetting that the box 1 exemption for 2026 expires February 15, 2027.
Filling in a K-4 when you only want standard withholding. With the flat tax, the form isn't needed then.

After You Fill It Out

Sign the K-4 and give it to your employer. Withholding can only stop once your employer has it. VergeHR keeps a copy in the person's folder in Files.

Keep a copy of the K-4 for your permanent records, as the form asks.

Your employer retains the K-4s it receives and may stop withholding for an employee who qualifies for an exemption.

Fill Out Kentucky Form K-4 Online with VergeHR

Pick the employee. Choose an employee and VergeHR fills in their name, date of birth, email and other details it already knows.
Answer plain-language questions. One part of the form at a time, with the official help text beside each question — 23 fields in all. Your answers save as you go.
Check the live preview. Watch your answers land on the real Kentucky Department of Revenue form, and let VergeHR do any worksheet arithmetic.
Generate the official PDF. VergeHR prints your answers into the agency’s own PDF and files it with that employee’s documents. Sign it, or send it for e-signature.

VergeHR fills the form — it never files or submits anything for you. Deliver the finished form to whoever asked for it, the way the form’s instructions say.

Start Kentucky Form K-4 Now — It’s Free

Kentucky Form K-4: frequently asked questions

Do I need a K-4 if I'm not exempt?

Only if you want additional withholding. The employer instructions say the K-4 is only required to document an exemption request or a request for additional withholding.

Why doesn't the K-4 ask for allowances?

Kentucky taxes wages at a flat 3.5% with a standard deduction allowance, so there is nothing to count.

Which states are reciprocal with Kentucky?

The form lists Illinois, Indiana, Michigan, West Virginia, Wisconsin, Virginia (if you commute daily) and Ohio (if you are not a 20%-or-greater S corporation shareholder-employee).

How long does the no-liability exemption last?

The 2026 form says the box 1 exemption expires February 15, 2027.

Why is it listed as KY-K-4 on VergeHR?

Kansas also calls its withholding certificate Form K-4, so VergeHR adds the state prefix to tell them apart. The form itself is Kentucky Form K-4 (42A804).

Official Sources

Blank form (PDF), published by Kentucky Department of Revenue: https://revenue.ky.gov/Forms/42A804%20(K-4)%20(2026).pdf
Official instructions and guidance: https://revenue.ky.gov/Forms/Pages/default.aspx
Edition shown on this page: 42A804 (K-4)(12-2025), tax year 2026 (checked 2026-09-28).

VergeHR is not affiliated with or endorsed by Kentucky Department of Revenue or any government. This page explains the form in general terms and is not legal, tax or immigration advice. Always read the official instructions, and check that you are using the edition the recipient accepts. Page last reviewed 2026-09-28.