A sales tax exemption number is a state-issued identifier that lets a qualifying buyer purchase goods or services without paying sales tax at checkout. Nonprofits, government agencies, and businesses buying inventory for resale are the most common holders, along with certain manufacturers, farms, and contractors. You get the number by applying to your state’s department of revenue, and you use it by giving vendors a completed exemption or resale certificate that carries the number on it.
Resale Numbers and Exemption Certificates Are Not the Same Thing
People use “sales tax exemption number” as a catch-all, but the term covers two different things.
A resale number (sometimes called a resale certificate number or seller’s permit number) goes to businesses that buy goods intending to sell them to end customers. The final customer pays sales tax at the retail level, so taxing the wholesale transaction would amount to double taxation. Retailers, wholesalers, and distributors use resale numbers when they buy inventory from suppliers.
An exemption certificate number goes to organizations whose purchases are exempt entirely. A church buying office supplies, a public school purchasing lab equipment, or a veterans’ organization buying event materials can skip sales tax because of what they are, not because they plan to resell anything. The tax is never collected at any point in the chain.
The distinction matters because the eligibility rules, the documentation, and the consequences of misuse are all different. A retailer using a resale number for personal purchases is committing fraud. A nonprofit using an exemption certificate for goods unrelated to its exempt purpose has the same problem.
Who Qualifies
Nonprofits and Charitable Organizations
Organizations recognized under Section 501(c)(3) of the Internal Revenue Code are the most familiar exemption holders. These include charities, religious institutions, educational organizations, and groups organized for scientific or literary purposes.1Office of the Law Revision Counsel. 26 US Code 501 – Exemption From Tax on Corporations, Certain Trusts, Etc To qualify federally, the organization must be operated exclusively for its exempt purpose, with no earnings benefiting private individuals.2Internal Revenue Service. Exemption Requirements – 501(c)(3) Organizations
Here’s the trap: an IRS determination letter confirming your 501(c)(3) status does not automatically grant a state sales tax exemption. Most states require a separate application to their own revenue department. Some states exempt all 501(c)(3) organizations by default. Others limit the exemption to specific categories like religious or educational groups. A few states offer no sales tax exemption for nonprofits at all, regardless of federal status.
Government Agencies
Federal government agencies are exempt from state sales tax under the doctrine of intergovernmental tax immunity rooted in the Supremacy Clause. State and local government entities are likewise exempt when purchasing goods for official use, though the mechanism varies by state. These exemptions apply to direct purchases, not to purchases made by contractors working on government projects unless the contract specifically provides for it.
Businesses Buying for Resale
Any business that purchases goods intending to resell them to a final consumer can obtain a resale number. This covers a clothing store buying wholesale inventory, but also a manufacturer buying components it will incorporate into a finished product. The test is whether the item will eventually be sold to an end customer who pays sales tax on it.
Manufacturers
Manufacturers purchasing raw materials that become a physical part of a finished product qualify for exemption in most states. Raw steel that becomes part of an appliance, fabric that becomes a garment, chemicals that become a cleaning product. Equipment and tools used in the manufacturing process are treated differently. Most states tax machinery and tools that don’t become part of the finished product, though some offer separate exemptions for manufacturing equipment.
Agricultural Operations
Farms, ranches, and similar operations qualify for exemptions on purchases directly tied to production. Feed for livestock, seed, fertilizer, and equipment used primarily in farming generally qualify. Building materials and general office supplies typically do not, unless they fall under a specific carve-out in your state. The line runs along whether the purchased item is directly consumed in or essential to producing goods for sale.
Construction Contractors
Contractors sit in an unusual position. Materials that get physically incorporated into a structure (lumber, wiring, plumbing fixtures) are treated differently from the tools and equipment a contractor uses on the job. In most states, contractors are considered the end consumer of their tools and must pay sales tax on them. Whether a contractor pays sales tax on building materials or passes that obligation to the property owner depends on how the contract is structured. Under lump-sum contracts, the contractor usually pays sales tax on materials at the time of purchase. Under time-and-materials contracts, the contractor often acts as a retailer of materials and collects sales tax from the customer instead.
How to Apply
The application runs through your state’s department of revenue or its equivalent tax authority. Specifics vary by state, but the core requirements are consistent.
You’ll need your Federal Employer Identification Number (EIN), the nine-digit tax identification number the IRS assigns to businesses and organizations.3Internal Revenue Service. Employer Identification Number Your legal entity name must match what’s on file with the Secretary of State and the IRS. You’ll provide a physical business address to establish your tax jurisdiction. Many states also ask for your NAICS code, the industry classification number that tells the revenue department what kind of business you operate and helps them verify that your claimed exemption category matches your actual activity.
Most states offer online applications through their revenue portals. The majority charge nothing for a basic sales tax registration or exemption certificate. Processing runs from near-instant on automated systems to several weeks where an application needs manual review. Nonprofits applying for organizational exemptions tend to face longer reviews than businesses registering for resale certificates, because the revenue department needs to verify exempt status.
If you haven’t yet formed your entity or obtained an EIN, handle those steps first. The IRS issues EINs online and immediately in most cases.4Internal Revenue Service. Instructions for Form SS-4
Using the Number at Checkout
Having the number is not enough. Before completing a purchase, you give the vendor a completed exemption or resale certificate that includes your state-issued number. Most states have their own certificate forms, and many vendors will hand you their preferred version at the point of sale.
You’ll generally choose between a single-purchase certificate covering one transaction and a blanket certificate covering all future purchases from that vendor. Blanket certificates are far more practical for ongoing supplier relationships. Under the Streamlined Sales Tax Agreement, a blanket certificate remains effective as long as purchases occur at least once every 12 months, unless the state allows a longer gap.5Streamlined Sales Tax Governing Board. Streamlined Sales Tax Certificate of Exemption
Sellers are not required to accept your certificate. The seller bears liability for uncollected tax if a certificate turns out to be invalid, so some vendors, particularly smaller businesses, may refuse to honor certificates they can’t easily verify. Frustrating, but legally within their rights.
Online Marketplaces
Major e-commerce platforms have their own systems for tax-exempt purchasing. Amazon’s Tax Exemption Program requires you to enroll through their Tax Exemption Wizard, providing your entity type, address, and exemption numbers or forms. Amazon does not accept sales tax permits, articles of incorporation, or W-9s as proof of exemption. You need the actual state-issued exemption certificate.6Amazon. Amazon Tax Exemption Program (ATEP) Most enrollments become active within 15 minutes, though applications requiring state-issued certificate uploads may take up to 24 hours for manual review. Other large platforms run similar programs, each with its own enrollment process.
Buying Across State Lines
If you buy from out-of-state suppliers, you’ll hit a patchwork of rules about which exemption certificates a vendor in another state will accept. There is no single certificate that works everywhere.
The Streamlined Sales Tax Agreement provides the closest thing to a standardized approach. Twenty-four states currently participate, 23 as full members and Tennessee as an associate member.7Streamlined Sales Tax Governing Board. Streamlined Sales Tax Governing Board Home In these states, the SST Certificate of Exemption is accepted as valid documentation, and member states cannot require sellers to independently verify exemption numbers.8Streamlined Sales Tax Governing Board. Relaxed Good Faith Requirement Member states will honor certificates from purchasers who aren’t registered in that state, which simplifies cross-border purchasing considerably.
Outside the SST states, the Multistate Tax Commission’s Uniform Sales and Use Tax Resale Certificate is another option. Roughly 38 states accept this form, though each state’s rules about registration requirements and acceptable documentation vary.9Multistate Tax Commission. Uniform Sales and Use Tax Resale Certificate Buyers using this form fill in the state-specific registration number for each state where they’re claiming an exemption.
Some states accept neither the SST nor the MTC form and insist on their own state-issued certificate. If you regularly buy from suppliers in those states, you’ll need to obtain and maintain the state’s specific form.
Drop Shipping
Drop shipping creates a three-party puzzle. The retailer takes the customer’s order, the supplier ships directly to the customer, and the retailer never physically handles the goods. The transaction between supplier and retailer is a resale and should qualify for exemption, but documentation gets tricky when the retailer has no sales tax registration in the state where the customer receives the goods.
Most states allow the supplier to accept alternate documentation, such as the retailer’s home-state resale certificate or a multi-state form, to substantiate the resale. About ten states are stricter and require their own state registration number on their own form. In some jurisdictions, if the retailer isn’t registered in the delivery state, the supplier is legally required to collect sales tax from the retailer even though the transaction is genuinely a sale for resale. If you operate a drop shipping business, map out the specific rules for every state you ship into.
Keeping Certificates Current
There is no national standard for how long a sales tax exemption certificate stays valid. Some states require annual renewal. Others set expiration dates at three, four, five, or ten years. A significant number of states issue certificates that never expire as long as the information is accurate and the business relationship is active. In SST member states, sellers cannot be required to obtain updated certificates as long as transactions occur at least once every 12 months.8Streamlined Sales Tax Governing Board. Relaxed Good Faith Requirement
If you buy from suppliers in multiple states, that inconsistency becomes an operational problem. A certificate that’s permanently valid in one state may have expired months ago under another state’s rules. Businesses that treat certificate management as a one-time task tend to find out during an audit, when they owe uncollected tax on purchases backed by expired documentation.
If your organization’s name, address, exemption category, or authorized representative changes, update your certificates with every vendor that has one on file. An outdated certificate with the wrong information may not protect you or the vendor during a review.
What Happens If You Misuse It
Using an exemption number for purchases that don’t qualify, like buying personal items with a business resale number, is fraud in every state. The consequences move quickly past just paying the tax you should have paid.
Under the SST Certificate of Exemption, a purchaser who improperly claims an exemption is liable for the full unpaid tax, interest, and possible civil and criminal penalties imposed by the state.5Streamlined Sales Tax Governing Board. Streamlined Sales Tax Certificate of Exemption Civil penalties in many states include a flat dollar amount per fraudulent certificate plus a percentage of the tax that should have been collected. Criminal prosecution for issuing false exemption documents is possible in most states and can result in fines and jail time. Corporate officers and managers responsible for collecting and remitting sales tax can face personal liability for unpaid amounts, even if the business itself is unable to pay.
The safe rule is simple: use your exemption number only for purchases that genuinely qualify under the category your state approved. If you’re unsure whether a particular purchase qualifies, pay the tax. Claiming a refund for an overpayment is a minor administrative task. Defending a fraud allegation is not.