How to fill out Kansas ST-21VT

The money-back half of Kansas's newest seller benefit. Since January 1, 2025, an individual who sells a vehicle within 120 days of buying another - either side of the purchase, privately or to a dealer - owes sales tax only on the difference. When the county treasurer could apply that credit at registration, no one needs this form; when they could not - you bought from a dealer, or sold after registering the replacement - this is how the Department refunds the excess. It wants both transactions' facts, the buyer of your old car, and the paper trail: sales tax receipt, bills of sale, and both titles front and back.

Written against ST-21VT (10-24), issued under K.S.A. 79-3697. This refund is arithmetic on two prices, and both must be provable: the reprinted statute kills the deduction if the taxpayer fails to provide the signed bills of sale, and substitutes tax on the full consideration. The TR-312 you signed on sale day - the one this site keeps telling Kansas sellers to keep a copy of - is the required exhibit. No copy, no difference, no refund.

Two documents, and they are not the same thing. Take the blank ST-21VT from the ksrevenue.gov copy so you get the revision that is current today, then print our ST-21VT guide and keep it beside you while you fill theirs in.

Every line, in the order you meet it

1. 1
   You fill this in

   Check the window and the direction

   One vehicle sold, one purchased, within 120 days of each other, either order, on or after January 1, 2025.

   Watch out: Also check who should be processing it: if you bought privately and have not registered yet, the county treasurer applies the credit at the counter and this form never enters the story.

2. 2
   You fill this in

   Part I and Part III

   You, with your Social Security number, and the person who bought your old car, with their address.

   Watch out: The buyer's details come off your TR-312 - one more reason that sheet gets completed properly on sale day rather than reconstructed from a text thread.

3. 3
   You fill this in

   Part II, both vehicles

   Year, make, VIN, price and date for the car sold and the car purchased.

   Watch out: The instructions even anticipate the lost VIN - it may be on an old insurance card or an old registration - but the prices must match the bills of sale and the titles, because the statute checks.

4. 4
   You fill this in

   The refund line

   Your arithmetic, or a blank the Department fills.

   Watch out: The refund is the tax on the amount your sale would have offset. When in doubt, leave it - the form's own line says the Department will calculate it for you, and a wrong figure slows a right claim.

5. 5
   You fill this in

   The exhibits

   Tick and attach: the sales tax receipt for the purchase, the dealer bill of sale if a dealer sold to you, the TR-312 from your sale, the old registration, and both titles front and back.

   Watch out: Copies of a title you have handed to a buyer feel impossible until you remember the photograph this site keeps telling you to take of the completed assignment - that photograph is this exhibit.

6. 6
   You fill this in

   Declare, sign, email

   The perjury declaration, the electronic-notice election, signature and date - then the packet to the audit services address, email preferred.

   Watch out: The claim stays open for three years from the replacement purchase, but every document on the checklist is easiest to gather in the week of the sale. File while the folder is still on the desk.

What gets this one rejected

• •No bill of sale for the car you sold. The instructions make it the required document for a private transaction - you may use Kansas Form TR-312 - and the statute reprinted on the form's second page denies the deduction entirely without the signed bills of sale.
• •Bills of sale that do not match the titles. The reprinted statute requires the sale price, date of sale and at least one buyer and seller on the bill of sale to match the assignment on the back of the certificate.
• •Claiming when the county could have done it. The instructions route the ordinary case - a private purchase registered at the treasurer's counter - through the trade-in credit at registration; the refund exists for the transactions county treasurers cannot process.
• •Selling more than one car against one purchase. The Department's notice on the new law is explicit that only one vehicle sold and one vehicle purchased can pair - multiple sales cannot stack against a single replacement.
• •A missing sales tax receipt. The refund is of tax you actually paid, and the receipt from the county treasurer or the dealer is the first required document on the checklist.

Rules that decide whether it is accepted

• •Either direction, 120 days. The window runs both ways - the sale can precede or follow the purchase - so a replacement bought in May and the old car sold in August still qualify.
• •The claim stays open three years. The Department's notice sets the limitation: valid claims filed within three years from the date of the purchase of the replacement vehicle. The paperwork ages better than the memory - assemble it now.
• •Email is the fast lane. The form's own instruction prefers email to the audit services address printed on it, with the documents scanned behind the request.

Every line here was read off ST-21VT (10-24) itself — the PDF is here — and off the Kansas Department of Revenue, Division of Vehicles pages. This is plain-language help with a form, not legal advice, and where our wording and the agency's differ, theirs governs.

Back to all Kansas seller paperwork, or what selling a car in Kansas involves.