Kansas Tax Exempt Form: Types, Filing, and Penalties

A Kansas tax exempt form is one of the ST-28 series certificates (or the numbered PR-78 for registered tax-exempt entities) that a qualifying buyer completes and gives to the seller at the point of purchase so the seller does not collect the 6.5% state sales tax. You do not send the form to the Kansas Department of Revenue; the seller keeps it on file as proof of why tax was not collected.¹² Choosing the wrong form, or checking the wrong exemption box on the right form, can void the exemption and expose both buyer and seller to back tax, interest, and in some cases criminal penalties.

Which Kansas Exempt Form You Need

The Kansas Department of Revenue publishes more than a dozen specialized certificates in the ST-28 series. Each one is tied to a specific legal basis for exemption, and using a certificate meant for a different situation will not save the transaction.

Form ST-28A, Resale Exemption Certificate. For businesses buying inventory they will resell. Only buyers registered to collect Kansas sales tax can use this form, and they must enter their Kansas registration number.³
Form ST-28, Designated or Generic Exemption Certificate. Used by entities whose exemption is based on what they are (such as schools or nonprofit religious organizations) by checking the box for their statutory exemption. Entities that have been assigned a Kansas Exemption Number cannot use this form and must use Form PR-78 instead.⁴⁵
Form PR-78, Tax-Exempt Entity Exemption Certificate. The numbered certificate the Department of Revenue issues to Kansas tax-exempt entities. It carries a printed expiration date and sellers should not accept it after that date.⁶
Form ST-28F, Agricultural Exemption Certificate. For farm machinery and equipment, seeds, feed, agricultural chemicals, fencing, and other items used exclusively in farming, ranching, or aquaculture.⁷
Form ST-28C, Consumed in Production Exemption Certificate. For materials and chemicals consumed during an industrial manufacturing process.
Form ST-28D, Ingredient or Component Part Exemption Certificate. For raw materials that become part of a finished product intended for sale.
Form ST-28M, Multi-Jurisdiction Exemption Certificate. For buyers operating across state lines, and the form out-of-state wholesalers generally use when they cannot use ST-28A.³

Other forms cover utilities (ST-28B), aircraft (ST-28L), interstate carriers (ST-28J), tire retailers (ST-28T), and other narrow situations. The Department of Revenue’s exemption certificates booklet lists every available form alongside its intended use.⁵

Information You Need to Complete the Certificate

Download the current version of the form from the Kansas Department of Revenue website. Before filling it in, have the following ready:

The purchaser’s legal name and address, matching the entity’s official records.
The Kansas Tax Registration Number, if the exemption is based on resale or on how the buyer will use the property. Businesses register through the Department of Revenue’s Customer Service Center.⁸
The seller’s business name and address.
The reason for the exemption, such as “resale,” “consumed in production,” or “agricultural use.”
A description of the property or services being purchased and how they will be used.

Check the box that matches your legal basis for the exemption. Checking the wrong category can void the certificate even when the buyer would otherwise qualify under a different provision.

Signature and Personal Liability

Paper certificates must be signed by an authorized representative of the purchasing entity. For nonprofits, that means an officer, office manager, or other administrator, and the signer’s driver’s license number must appear on the certificate.² Electronic certificates do not require a signature.¹ Signing the form acknowledges personal liability: if the property is later used in a taxable way, both the entity and the individual who signed can be held responsible for the tax.

Nonprofit Purchases

Federal 501(c)(3) status does not, on its own, exempt an organization from Kansas sales tax. Only entities specifically listed in the Kansas sales tax statutes qualify, and Kansas-based exempt entities must obtain a Kansas Tax-Exempt Entity Exemption Number and use the numbered PR-78 certificate rather than the generic ST-28. Out-of-state exempt entities that regularly do business in Kansas are encouraged to apply for a Kansas exemption certificate through the Department of Revenue’s website.⁵

The exemption applies only to direct purchases by the entity for its exclusive use. The purchase must be billed to the entity or paid with the entity’s funds. An employee who pays with a personal credit card and gets reimbursed later owes tax on the purchase, even if the organization itself would have been exempt.⁵

Out-of-State Buyers

A business based outside Kansas that is not registered to collect Kansas sales tax generally cannot use Form ST-28A with a home-state tax ID number. Out-of-state wholesalers and buyers should use Form ST-28M, the Multi-Jurisdiction Exemption Certificate, instead.³

There is a narrow exception for drop shipments. An out-of-state retailer with Kansas sales tax nexus that has inventory drop-shipped to a Kansas location must provide the third-party vendor with a Kansas sales tax registration number. An out-of-state retailer without Kansas nexus may provide a resale exemption certificate from whatever state it is registered in.³

Project Exemption Certificates for Construction

Governments, schools, hospitals, and certain other statutorily identified organizations can obtain a Project Exemption Certificate (PEC) for a construction project. The PEC allows a contractor working for the exempt entity to buy building materials and supplies tax-free, so the entity does not indirectly pay tax through the contractor’s markup. To apply, the exempt entity signs in to the Department of Revenue Customer Service Center, selects “Project Exemption Certificate / Agent Status,” and completes the application online. Questions go to 785-296-3081 or kdor_exemptcert@ks.gov.⁹

Direct Pay Permits

Businesses with complicated purchasing operations can apply for a Direct Pay Permit that lets them buy everything tax-free and then self-assess the correct state and local tax based on how each item is actually used. To qualify, a business must either make at least $1 million in annual purchases of tangible personal property for business use (not resale) or show that taxability is genuinely difficult to determine at the point of purchase. The application goes to the Secretary of Revenue, who has 90 days to respond.¹⁰

Giving the Certificate to the Seller

Hand the completed certificate to the vendor at the time of purchase. The seller keeps the original and must produce it if the Department of Revenue asks.² Keep your own copy for at least three years from the end of the calendar or fiscal year the records cover, which matches the period during which the Department of Revenue can inspect records and assess additional tax.¹¹

Blanket Certificates for Repeat Purchases

When you buy from the same vendor regularly, one blanket certificate can cover every qualifying transaction. Kansas law treats a blanket certificate as still valid as long as a “recurring business relationship” exists, meaning no more than 12 months elapses between sales, and the certificate does not otherwise need to be renewed.⁶ The Department of Revenue still recommends verifying blanket certificates annually so that names, locations, and account numbers stay current.¹² The PR-78 Tax-Exempt Entity Exemption Certificate is different: it carries a printed expiration date, and sellers should not accept it past that date.

If You Paid Tax You Should Not Have

Buyers who paid sales tax on a purchase that qualified for exemption can file for a refund using Form ST-21, the Sales and Use Tax Refund Application. The form requires a detailed schedule of each invoice date, vendor, item description, price, and tax paid, plus the statutory reason the purchase was exempt. In most cases, the retailer completes Part E to assign the refund right to the buyer. If the retailer is out of business, has moved, or will not cooperate, the buyer completes Part F as an affidavit explaining why. The application is signed under penalty of perjury.¹³ Refund claims generally follow the same three-year window as assessments, so do not sit on them.¹¹

Penalties for Misusing the Form

Issuing a resale or other exemption certificate to unlawfully avoid tax for business or personal gain is a misdemeanor in Kansas, punishable by up to $1,000 in fines, up to one year in jail, or both. On top of criminal exposure, the Department of Revenue will impose a civil penalty on each fraudulent transaction of $250 or 10 times the tax that should have been paid, whichever is greater.¹

Even without fraud, late payment of sales tax triggers a penalty of 1% per month on the unpaid balance, capped at 24% for voluntary filings or 10% for amounts found during a field audit, plus 8% annual interest for 2026.¹⁴ If you discover that property you bought tax-free was used in a taxable way, report and pay the compensating use tax voluntarily rather than waiting for an audit to find it.

1
Kansas Legislature. Kansas Statutes 79-3651
2
Legal Information Institute. Kansas Administrative Regulations 92-19-25b – Exemption Certificates
3
Kansas Department of Revenue. Resale Exemption Certificate
4
Kansas Department of Revenue. About the Designated Exemption Certificate, Form ST-28
5
Kansas Department of Commerce. Kansas Department of Revenue Exemption Certificates Booklet
6
Kansas Department of Revenue. Publication KS-1520 Exemption Certificates
7
Kansas Department of Revenue. ST-28F Agricultural Exemption Certificate
8
Kansas Department of Revenue. Business Registration
9
Kansas Department of Revenue. Exemption Certificate Welcome Page
10
Legal Information Institute. Kansas Administrative Regulations 92-19-82 – Direct Pay Permits
11
Kansas Office of Revisor of Statutes. Kansas Statutes 79-3609
12
Kansas Department of Revenue. Pub. KS-1510 Sales Tax and Compensating Use Tax
13
Kansas Department of Revenue. Sales and Use Tax Refund Application
14
Kansas Department of Revenue. Penalty and Interest