How to Complete and File the Kansas KW-3 Withholding Tax Return

The Kansas KW-3 withholding tax return is the annual reconciliation Kansas employers file by January 31 to match the state income tax they withheld from wages and payments during the prior calendar year against the deposits they actually sent to the Kansas Department of Revenue.¹ If those two numbers don’t line up, the form produces either a balance due or a credit you can carry forward.

Who Has to File

Every employer registered with the Kansas Department of Revenue for withholding tax must file a KW-3. That includes any business that issued W-2 or federal 1099 forms showing Kansas withholding for the year.²

Withheld nothing during the year? You still file. Submit a zero return so Kansas can close out the reporting period; skipping it invites delinquency notices on an account the state still considers active.²

One boundary worth knowing: if you paid a 1099 contractor and no Kansas tax was withheld from the payment, the federal Combined Federal/State Filing program handles the Kansas reporting, and that payee does not need to be listed on your KW-3.¹

When Electronic Filing Is Required

Employers with 51 or more employees or payees must file the KW-3 and submit their W-2 and 1099 reports electronically through the Kansas Department of Revenue Customer Service Center.³ Below that threshold, paper or electronic filing is your choice.

What to Pull Together Before You Start

You will move faster if these are on the desk before you open the form:

Your nine-digit federal Employer Identification Number (EIN).
Your Kansas Tax Account Number, printed on prior KW-5 deposit reports and Department correspondence.
Copies of every W-2 and 1099 showing Kansas withholding, plus a count of them.
Your KW-5 deposit reports for the year, since each deposit gets listed on the back of the KW-3.
Any credit memo issued by the Department for a prior-year overpayment.

Paper filers must attach copies of all W-2 and 1099 forms to the KW-3. If you filed the KW-3 electronically but are sending W-2s and 1099s on paper, print your electronic confirmation and include it with the paper reports.⁴

Filling Out the Form

The KW-3 has two working areas: five main lines on the front (A through E), and a payment schedule on the back where you list every deposit made during the year. Do the back first, because Line B on the front comes from that total.

Back of the Form: The Payment Schedule

The schedule matches your filing frequency: semi-monthly (24 periods), monthly (12), or quarterly (4). Enter the Kansas withholding you deposited for each period, add the entries, and carry the total to Line B on the front.¹ Check each figure against your KW-5s. This is where most mismatches start.

Front of the Form: Lines A Through E

Line A: Total Kansas income tax withheld from all employees and payees, taken from the W-2s and 1099s showing Kansas withholding. This is what you were supposed to deposit for the year.
Line B: Total Kansas withholding actually paid during the calendar year, carried over from the schedule on the back.
Line C: Any prior-year credit memo amount you are applying. Zero if none.
Line D: Lines B and C added together. Do not include amounts paid toward penalties or prior-year liabilities.
Line E: The difference between Line A and Line D. If they match, this line is zero. If not, it shows either an underpayment or an overpayment.

The form does not ask for gross wages. Only the Kansas withholding numbers and your deposits belong here.

If You Underpaid

When Line D is less than Line A, you owe the shortfall. The preferred method is to complete a KW-5 Withholding Deposit Report for the period of the underpayment, and send it in with your payment, the KW-3, and the W-2/1099 forms. Using a separate KW-5 to report the underpayment (with any penalty and interest) lets you skip Lines F, G, and H on the KW-3. If you don’t have a blank KW-5 available, use Lines F, G, and H on the KW-3 instead.¹

If You Overpaid

When Line D exceeds Line A, put the overpayment on Line E and again on Line H. Kansas will issue a credit memo you can apply against next year’s withholding.¹

How and Where to File

Sign and date the return and include a phone number where the Department can reach you. The deadline is January 31 following the close of the calendar year, and Kansas offers no specific extension for the KW-3.¹

To file online, use the Kansas Customer Service Center at ksrevenue.gov. The portal handles original, amended, and additional returns and issues a confirmation number when the submission goes through.³

To file by mail, send the completed KW-3, all enclosed W-2 and 1099 copies, and any payment to:

Kansas Department of Revenue
PO Box 3506
Topeka, KS 66625-3506¹

Make checks payable to the Kansas Department of Revenue and write your Kansas Tax Account Number on the check. The postmark must be on or before January 31 to avoid a late-filing penalty.

What Late or Missing Payment Costs

Kansas assesses penalties on the underpayment, and the rate climbs with how late the money arrives:⁵

1 to 5 days late: 2% of the underpayment.
6 to 15 days late: 5%.
More than 15 days late: 10%.
More than 15 days late after a Department notice, and not paid within 10 days of that notice: 15%.

On top of those rates, Kansas adds 1% per month, up to 24%, on any unpaid tax balance. If the Department sends written notice of a delinquent return and you do not file within 20 days, an additional 50% penalty can be assessed on top of everything else.⁵

Interest runs separately. For 2026, the rate is 8% per year, or 0.67% per month or fraction of a month.⁵ A six-month delay on even a modest underpayment can nearly double the amount owed once the tiered penalty, the monthly surcharge, and interest are combined.

Fixing an Error After You File

If you catch a mistake after the return is in, file an amended KW-3. The form has checkboxes for “Amended Return” and “Additional Return.” Check the correct box, enter the corrected figures, and submit either on paper or through the Customer Service Center.¹ File the correction quickly. If the original error was an underpayment, penalty and interest continue to accrue until it’s paid.

Closing the Withholding Account

When a business closes or stops paying wages in Kansas, file all outstanding returns, including a final KW-3 for the last calendar year of operations, and pay any remaining balance. Then formally close the withholding account with Form CR-108 (Notice of Business Closure), sent to the Kansas Department of Revenue at PO Box 3506, Topeka, KS 66625-3506, or faxed to 785-291-3614.⁶ An open account with no filings generates zero-return delinquency notices, so close it out as soon as operations end.

1
Kansas Department of Revenue. Kansas Form KW-3 – Annual Withholding Tax Return
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Kansas Department of Revenue. Frequently Asked Questions About Withholding
3
Kansas Department of Revenue. Electronic Withholding Requirements
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Kansas Department of Revenue. W-2 and 1099 Frequently Asked Questions
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Kansas Department of Revenue. Penalty and Interest
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Kansas Department of Revenue. Business Closed, Sold or No Activity to Report