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New York State Sales Tax Guide
New York sales & use tax

Exemption certificates: resale, contractor, exempt-use and exempt-organization

A properly completed certificate lets a purchaser buy tax-free — but the paperwork has to move within 90 days, the seller can still say no, and the record has to survive three years.

Reviewed against published state sources on September 15, 2026. Rules and figures change — always confirm with the agency before acting.

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An exemption certificate is the paperwork that lets a purchase happen without sales tax being charged on something that would normally carry it. Tax Bulletin TB-ST-240 puts the mechanics simply: the purchaser fills the certificate out and hands it to the seller, the seller keeps it on file, and from then on that seller can sell to that purchaser — under the terms the certificate describes — without collecting tax.

The two questions worth answering before anything else: which certificate actually fits the purchase, and does the seller have to accept it. The answer to the second one is no — a seller can refuse any exemption certificate, correct or not, and if they do, they have to charge tax. A refused certificate is not a dead end for the purchaser; it just means the tax gets paid up front and clawed back afterward with Form AU-11.

Which certificate, for which purchase

CertificateUsed forPurchaser needs a Certificate of Authority?
ST-120, Resale CertificateProperty or services the purchaser will resell, unused, in the ordinary course of businessYes, unless the purchaser is an out-of-state business
ST-120.1, Contractor Exempt Purchase CertificateProperty to be incorporated into real property, and related services — for contractors in place of ST-120Yes
ST-121, Exempt Use CertificateProperty or services bought for a use the law exempts — covers a wide range of specific exemptionsDepends on the exemption being claimed
ST-119.1, Exempt Organization Exempt Purchase CertificatePurchases by an organization already holding Form ST-119 (its own exempt-organization certificate)No — the ST-119 number stands in for it

ST-120 is explicitly off-limits to construction contractors — they use ST-120.1 instead, because a contractor is treated as the end consumer of the materials they install, not as a reseller of them.

Getting to a Form ST-119.1 in the first place

ST-119.1 only works if the organization already holds Form ST-119, the Department's Exempt Organization Certificate, which carries a six-digit exemption number. Getting there means filing Form ST-119.2, Application for an Exempt Organization Certificate, and showing the Department the organization is formally organized and operated exclusively for an exempt purpose — religious, charitable, educational, and similar categories qualify. A 501(c)(3) determination letter from the IRS, where the organization has one, goes in with the application.

Not every exempt-sounding entity needs to go through this. Governmental bodies — New York State and U.S. government entities, the United Nations and comparable international organizations, U.S. armed forces posts — are already exempt and don't file ST-119.2 at all. Organizations exempted by some other state or federal statute are in the same position. Other states and their political subdivisions are the opposite case: they don't qualify for New York's exemption in the first place.

The 90-day rule cuts both ways

The purchaser has to give the seller a properly completed certificate within 90 days of the purchase — sooner is better, and TB-ST-240 says the time of sale is preferable. Miss the window and both sides can end up on the hook for the tax that was never collected, not just the purchaser.

Good faith, and what it actually requires of a seller

A seller who accepts a properly completed certificate in good faith is protected from liability for the tax not collected. Good faith here has a specific, narrow meaning: no prior knowledge that the certificate was false or fraudulent, and ordinary care taken in accepting it. A seller who already knew the purchase wasn't for an exempt purpose, or knew the certificate was fabricated, doesn't get the protection — and can be assessed for the uncollected tax regardless of the paperwork on file.

Certificates issued by other states or countries carry no weight here. A resale or exemption certificate valid in New Jersey or Connecticut does not exempt a New York sale; the purchaser needs the New York form.

Blanket certificates, for repeat business

A purchaser who buys the same category of exempt goods from the same seller repeatedly doesn't have to file a fresh certificate every time. Marking the blanket-use box on an eligible certificate — ST-120 and ST-121 both allow it — covers every similar purchase from that seller going forward, until the purchaser's details change or the seller asks for an update. A seller is entitled to ask for a refreshed blanket certificate at any point, and the purchaser has to supply one if anything on file — address, identification number, anything else the certificate requires — has changed.

What the seller has to keep, and for how long

Three years, tied to the return

A seller must keep an accepted exemption certificate — attached to the record of the purchase, or otherwise clearly linked to it — for at least three years from the due date of the sales tax return on which the last sale made under that certificate was reported. That clock is anchored to the return, not to the date the certificate was signed, which matters most for a blanket certificate covering purchases over a long stretch of time.

Misuse has real consequences

Issuing a certificate the purchaser knows to be false — claiming resale for goods actually being used, for instance — is not a paperwork error the Department treats lightly. TB-ST-240 points to Tax Bulletin TB-ST-805 for the penalty structure, and willful or knowing misuse can carry fines or a jail sentence on top of the tax itself.

Common questions

Can a seller refuse a valid New York exemption certificate?
Yes. A seller may refuse any exemption certificate, even one that is correct and properly completed. If they refuse it, they must charge sales tax, and the purchaser can seek a refund afterward using Form AU-11.
What is the deadline for giving a seller an exemption certificate?
Within 90 days of the purchase, though the Department says giving it at the time of sale is preferable. Missing the 90-day window can expose both the purchaser and the seller to liability for the uncollected tax.
Does a resale certificate from another state work in New York?
No. Exemption certificates issued by other states or countries are not valid for New York State and local sales and use tax. A New York purchase needs a New York certificate.
How long does a seller have to keep an exemption certificate on file?
At least three years from the due date of the sales tax return on which the last sale made under that certificate was reported, per Tax Bulletin TB-ST-770 on record-keeping.
Can a contractor use a Resale Certificate (ST-120)?
No. Form ST-120 explicitly excludes construction contractors, who use Form ST-120.1, the Contractor Exempt Purchase Certificate, instead.

Sources

  1. TB-ST-240, Exemption Certificates for Sales Tax — https://www.tax.ny.gov/pubs_and_bulls/tg_bulletins/st/exemption_certificates_for_sales_tax.htm
  2. Sales tax exempt organizations — https://www.tax.ny.gov/bus/st/exempt.htm
  3. Sales tax exemption documents (forms index) — https://www.tax.ny.gov/forms/sales_tax_exemption_documents.htm
  4. TB-ST-770, Record-keeping Requirements for Sales Tax Vendors — https://www.tax.ny.gov/pubs_and_bulls/tg_bulletins/st/record_keeping_requirements_for_sales_tax_vendors.htm