To get a certificate of authority to collect sales tax, you register with the tax department of every state where your business has sales tax nexus, using that state’s online portal (or the multi-state Streamlined system) and supplying your federal EIN, entity details, responsible-party information, and an estimate of your taxable sales. Registration is free in most states, often approved within a few business days online, and must be completed before you make your first taxable sale.
The certificate goes by different names depending on the state — sales tax permit, seller’s permit, certificate of authority — but the function is the same: it designates your business as the state’s collection agent and is the only legal basis for charging sales tax to your customers.
Figure Out Where You Need to Register
Two things create a registration obligation: physical presence and economic nexus.
Physical presence is the older trigger. Owning or leasing property in a state, keeping inventory in a warehouse or fulfillment center there, or having employees or sales representatives working in the state all establish physical presence, and each one obligates you to register before making taxable sales in that state.
Economic nexus catches remote sellers who have no physical footprint. The U.S. Supreme Court authorized these laws in 2018 in South Dakota v. Wayfair, Inc., and every state with a sales tax has since enacted one. The most common threshold is $100,000 in gross sales into the state during the current or prior calendar year. A handful of states set the dollar threshold higher, at $250,000 or $500,000, and about 16 states as of mid-2025 still use a transaction-count alternative (typically 200 separate transactions). Because the thresholds and measurement periods differ, track your sales into each state separately.
Five states have no general sales tax and no registration to obtain: Alaska, Delaware, Montana, New Hampshire, and Oregon. Alaska is a partial exception because some Alaska municipalities levy their own local sales taxes, so shipping into certain Alaska localities can still create a collection duty.
Check Whether a Marketplace Already Collects for You
If your sales run through Amazon, Etsy, Walmart Marketplace, or a similar platform, the platform itself may be handling the tax. Every sales-tax state now has a marketplace facilitator law requiring the platform to collect and remit on behalf of its third-party sellers once the platform’s own sales into the state cross the economic nexus threshold.
That does not automatically clear you. Some states still require the individual seller to register, file returns, and report the platform-facilitated sales even though the platform sent in the tax. And any sales you make off the marketplace — through your own website, at a craft fair, wholesale to a business — remain your responsibility. The conservative approach is to register in every state where you have nexus regardless of how the sales are channeled.
Gather What the Application Requires
Before you open a state’s application, have the following ready.
A Federal Employer Identification Number from the IRS. This nine-digit number identifies your business on nearly every state tax registration. Sole proprietors with no employees can sometimes substitute a Social Security number, but an EIN keeps personal information off documents that vendors and customers may see. Applying is free and takes minutes on the IRS website.
Your legal business name exactly as it appears on your formation documents, your physical business address (most states will not accept a P.O. box as the primary location), and your entity type. You will also enter personal information, including Social Security numbers, for all responsible parties: owners, partners, or corporate officers. States collect this because those individuals can be held personally liable for unremitted tax.
A projected figure for monthly taxable sales. Tax departments use it to assign your filing frequency — monthly for higher-volume sellers, quarterly for moderate volume, annual for the smallest operations. You will also identify your industry, usually by selecting a North American Industry Classification System (NAICS) code, and describe the goods or services you sell. Accurate answers here prevent delays and ensure you receive rate information for the right product categories.
How to Apply in a Single State
Most states register businesses through an online tax portal. You create an account, enter the business information, upload any supporting documents, and submit electronically. Online applications typically generate a confirmation number immediately and let you track status. Paper filings are still accepted in most places but take longer.
Registration is free in the majority of states; a few charge a small fee. Some states may require a security deposit or surety bond before issuing the certificate, especially if the business or its owners have a history of tax delinquency or operate in an industry the state considers high-risk. Bond amounts are usually calculated as a multiple of estimated tax liability and are typically refundable once you build a clean compliance record.
Processing times depend on the state and the filing method. Electronic applications are often approved within a few business days; paper submissions can take several weeks. Most states require registration before your first taxable sale, and some specify at least 20 days in advance. Do not begin collecting sales tax until the certificate has actually been issued — collecting without one is itself unlawful.
Registering in Multiple States at Once
If you sell into many states, filing a separate application in each one is a substantial project. The Streamlined Sales and Use Tax Agreement, an interstate compact with 23 full member states, exists to reduce that work. Through the Streamlined Sales Tax Registration System, you can register for sales tax in every participating state with one online application, free of charge.
Member states also standardize their tax bases, definitions, and sourcing rules, which makes ongoing compliance easier once you are in. State-level administration means one return and one payment per member state rather than filings for individual local jurisdictions. Member states are also generally barred from auditing businesses that registered voluntarily through the system, which is a meaningful protection for sellers coming into compliance on their own initiative.
After You’re Approved
Most states require you to display the certificate in a conspicuous location at your place of business. Sellers who work from carts, trucks, or booths generally have to keep the certificate attached to their merchandising setup. Failure to display can carry fines that accumulate daily.
The certificate is tied to a specific legal entity and a specific address. If you change your business structure, add a partner, or relocate, notify the state tax department promptly so the registration stays current. Some states issue certificates that remain valid indefinitely as long as the information on file is accurate; others require periodic renewal. A lapsed registration is legally the same as no registration.
A resale certificate is a separate document you may also need. Your certificate of authority lets you collect tax from end consumers. A resale certificate is what you give your suppliers to buy inventory tax-free because the tax will be collected when you sell the goods on. It only covers merchandise you genuinely plan to resell; anything you divert to business use or personal use creates a use tax liability. Expiration rules vary by state — annual renewal in some, multi-year or indefinite validity in others — and keeping supplier certificates organized matters because a missing or expired one can leave you owing the uncollected tax with interest and penalties during an audit.
If you only sell at occasional events like craft fairs, festivals, or holiday markets, most states offer a temporary or event-based permit covering a selling period of 90 days or less at a single location, rather than requiring a full certificate of authority. If you already hold a permanent permit for your regular business, you generally register the temporary location as a sub-permit under your existing account instead of applying separately.
What Happens If You Skip Registration
Selling without a valid certificate of authority is treated as a criminal offense in most states, typically a misdemeanor on a first offense with escalating fines and possible jail time on repeat violations. Some states count each day of unpermitted operation as a separate violation.
The financial exposure is often the bigger problem. The state can assess back taxes for every period you should have been collecting, plus interest from the original due dates, plus late-payment and failure-to-file penalties on top. Sales tax you collect from customers is legally trust fund money that belongs to the state, and officers, directors, partners, and anyone else with authority over business finances can be held personally liable for unremitted amounts. That personal liability generally survives the corporate or LLC shield and generally cannot be discharged in bankruptcy.
If you realize you should have been registered in a state and were not, a voluntary disclosure agreement can significantly limit the damage. Most states offer these programs to businesses that come forward before being contacted by auditors. A typical agreement caps the look-back at three years and waives all penalties in exchange for your cooperation; you still owe the tax and interest. Eligibility usually ends once the state has already flagged you or sent a notice, so the value of the program depends on acting before that happens.