A sales tax certificate is the registration a state issues that authorizes your business to collect sales tax from customers, remit it to the state, and buy inventory tax-free for resale. Every state that imposes a sales tax requires you to hold one before your first taxable transaction. Only five states have no statewide sales tax — Alaska, Delaware, Montana, New Hampshire, and Oregon — and even Alaska allows local jurisdictions to impose their own. In the other 45 states and Washington, D.C., this document is the legal foundation for collecting tax from customers and the paperwork suppliers will ask for when you want to buy stock without paying tax up front.
Who Needs to Register
If you sell tangible goods or taxable services to consumers, you almost certainly need to register somewhere. The concept that decides where is nexus: the legal connection between your business and a state that gives the state the right to require you to collect its tax. Nexus takes two forms, and either one triggers a registration obligation.
Physical nexus exists when your business has a tangible presence in a state: an office, warehouse, retail location, inventory sitting in a fulfillment center, or employees working there. If you have people or property in the state, you have nexus.
Economic nexus is the newer standard. In 2018 the U.S. Supreme Court decided South Dakota v. Wayfair, Inc., upholding a South Dakota law that required out-of-state sellers to collect sales tax if they delivered more than $100,000 in goods or services into the state, or completed 200 or more separate transactions there, on an annual basis.1Supreme Court of the United States. South Dakota v. Wayfair, Inc. Every state with a sales tax has since set its own threshold. The most common trigger is $100,000 in annual sales, though some states set a higher bar. A growing number have dropped the transaction-count test and now use only a dollar threshold; as of early 2026, at least 15 states — including South Dakota, Colorado, Indiana, Washington, and Illinois — have done so.2Sales Tax Institute. Economic Nexus State by State Chart
The practical result: if you sell online and ship across state lines, you may have registration obligations in states where you have never set foot. Check each state’s threshold individually before you assume you’re clear.
If You Sell Through a Marketplace
Selling through Amazon, Etsy, eBay, or Walmart Marketplace changes the picture. Nearly every state with a sales tax now has a marketplace facilitator law that shifts collection and remittance for platform sales onto the platform itself. Amazon calculates, collects, and sends the tax for orders it fulfills; you don’t do it for those transactions.
That does not automatically excuse you from registering. If you also sell through your own website, at trade shows, or from a physical storefront, those direct sales are still yours to handle, and you need your own certificate in each state where you have nexus for them. Some states also require registration even from sellers who use marketplaces exclusively. Read your state’s specific rule before assuming the platform has covered everything.
How to Apply
Registration goes through your state’s department of revenue or equivalent tax agency, almost always via an online portal. Have the following ready before you start:
- Your legal business name exactly as it appears on formation documents, plus your Federal Employer Identification Number (EIN) if you have one, or your Social Security Number if you’re a sole proprietor.
- Your business structure: LLC, corporation, partnership, or sole proprietorship.
- Your NAICS code, the classification that describes your primary business activity. The Census Bureau’s website lets you look it up.
- Names, addresses, and contact information for all owners, partners, or corporate officers. States collect this because these people can be held personally liable for unremitted sales tax.
- The physical address where you conduct sales, and any additional locations.
Registration is free in most states. A few charge a small fee or ask for a deposit, but the widespread belief that applications cost significant money is wrong. Be wary of third-party sites that charge to file what is otherwise a free application. Start at your state tax agency’s official website.
Processing varies. Online applications are often approved in a few days and sometimes instantly; paper applications take longer. Once approved, you’ll receive your certificate, often as a downloadable document, with the sales tax identification number you’ll use on every future filing.
Bonds and Temporary Permits
Some states require a surety bond before issuing a certificate, mostly for businesses with a history of tax delinquency or in regulated industries like alcohol and tobacco retail. The bond guarantees you’ll remit what you collect, and the amount is usually tied to your expected tax liability. Clean records rarely trigger a bond requirement.
If you’re selling at a craft fair, festival, or other short-term event, most states offer a temporary sales tax license instead of full registration. These cover a single event or a short defined period, and they typically require you to file and pay shortly after the event ends, often within 10 days.
Buying Inventory Tax-Free
The immediate practical payoff of holding a certificate is that you can buy goods for resale without paying sales tax at the register. You give your supplier a resale certificate, or a copy of your sales tax certificate depending on the state, and the supplier keeps it on file and doesn’t charge you tax. Tax gets collected once, when you sell the item to the final consumer.
The exemption covers goods you intend to resell and raw materials or components that become part of a finished product you sell. It does not cover equipment, office supplies, or anything your business uses internally. A restaurant can buy ingredients tax-free because it resells them as meals; the oven it cooks them in is taxable.
Do not use a resale certificate to dodge tax on personal purchases. States take this seriously. Consequences include back taxes on every improperly exempted purchase, penalties that in some states run to 100% of the tax due, interest, and possible revocation of your certificate. Fraudulent use can bring criminal charges.3New York State Department of Taxation and Finance. ST-120 – Resale Certificate
If you buy from suppliers in multiple states, the Streamlined Sales Tax program offers a uniform exemption certificate accepted across its 24 full member states.4Streamlined Sales Tax Governing Board. Streamlined Sales Tax Certificate of Exemption It works as a single-purchase or blanket certificate; the blanket version stays valid as long as you make purchases at least every 12 months. For states outside that system, you’ll usually need each state’s own form. When in doubt, ask your supplier which form they need.
After You’re Registered
The certificate is the starting point. The ongoing obligation is filing returns and sending in what you’ve collected on the schedule the state assigns. Most states set your filing frequency — monthly, quarterly, or annually — based on your sales volume. A business collecting around $600 or more per month in sales tax typically files monthly; low-volume sellers may file quarterly or annually.
File every period, even ones where you collected nothing. A zero return is still a return. Skipping a filing because you had no sales generates a delinquency notice and can bring penalties; the state treats a missing return the same whether you owed $10,000 or nothing.
Late filing and late payment each carry their own penalties, usually a percentage of unpaid tax that grows the longer you wait, plus interest from the original due date. Many states require electronic filing and payment above a certain volume.
Renewal and Recordkeeping
Whether your certificate ever needs renewal depends on the state. In many, including California, Georgia, Kansas, Kentucky, and Iowa, your permit stays valid indefinitely as long as you keep operating and filing. Others renew on a set cycle: annually in some cases, every two to five years in others. A handful renew automatically as long as you’re current. Check your specific state rather than assuming a renewal is coming.
Report changes to the state promptly. Moving your business, changing its legal name, restructuring ownership, or adding a location all require updates. Mismatches trigger audit flags and delayed correspondence.
Many states require you to display your certificate at your place of business where customers can see it. It’s not just a formality; it demonstrates your authority to collect tax and matters during a compliance inspection.
Keep sales records, exemption certificates you’ve received from buyers, and filed returns for at least three years from the return’s due date, longer if your state requires it or if you’re under audit. Some states can look back four or more years. Resale certificates you accepted from customers are especially important — without them, you have no documentation for why you didn’t collect tax on those sales, and the liability shifts to you.
What Happens If You Skip It
Operating without a required certificate carries real consequences. Penalties vary by state and can include daily fines for each day of unregistered sales, back taxes, interest, and criminal charges for willful evasion. You’ve also been collecting tax from customers, or should have been, without any authority to do so, and the state will want every dollar.
The part that catches owners off guard is what happens to tax you did collect but didn’t remit. Sales tax collected from customers is not your money. It’s held in trust for the state, and that distinction has teeth. If your business fails to remit collected tax, whether from cash flow trouble, negligence, or intentional diversion, the state can pursue the individuals responsible, not just the business entity. Officers, directors, managing members, and employees with authority over the company’s finances can be held personally liable for the full unremitted amount, plus penalties and interest. The business structure that normally shields your personal assets from company debts does not shield you from trust fund obligations like collected sales tax.
States look at authority over financial decisions, ability to sign tax returns, control over which creditors get paid, and day-to-day involvement in operations when identifying responsible individuals. If you had the power to direct the company’s tax payments and didn’t make them, you’re on the hook personally. Staying hands-off from your own company’s sales tax filings can turn into one of the most expensive mistakes you make.