No, a sales tax ID is not the same as an EIN. An Employer Identification Number is a nine-digit federal number the IRS assigns to identify your business for income tax, payroll, and other federal obligations. A sales tax ID is a state-issued number that authorizes your business to collect and remit sales tax on taxable goods and services. Different government, different tax, different form. Most businesses that sell taxable goods end up needing both.
What the EIN Is
The EIN is your business’s federal tax identifier. The IRS uses it to track everything owed at the federal level: income tax, payroll tax, unemployment tax, and excise tax.1Internal Revenue Service. Employer Identification Number
You’re required to have one if your business is a partnership, LLC, or corporation. You also need one if you hire employees, withhold taxes on payments to a non-resident alien, or owe excise taxes on alcohol, tobacco, or firearms. Sole proprietors with no employees are the exception; they can use their Social Security Number instead.1Internal Revenue Service. Employer Identification Number
Even sole proprietors who qualify to skip it usually get one anyway. Banks typically want an EIN before they’ll open a business account, and using it on contracts and vendor forms keeps your SSN off documents that pass through other people’s hands.
Applying is free. The online application at IRS.gov takes about ten minutes and issues the number on the spot.2Internal Revenue Service. Get an Employer Identification Number Any website charging a fee is filling out the same free Form SS-4 and marking it up.1Internal Revenue Service. Employer Identification Number
Once issued, the EIN goes on every federal tax return your business files: corporate returns, partnership returns, quarterly payroll filings reconciling federal withholding and Social Security and Medicare tax, and annual FUTA returns. It also appears on every W-2 you issue to an employee and every 1099 you issue to a contractor. Without a valid EIN, the IRS won’t accept those filings.3Internal Revenue Service. Instructions for Form 940 (2025)
What a Sales Tax ID Is
A sales tax ID is a number issued by a state taxing authority. It gives your business the legal right to collect sales tax from customers and remit it to the state. States use different labels for the same thing: seller’s permit, sales tax license, resale certificate number, state tax ID. The name shifts by state; the function doesn’t.
Five states impose no statewide sales tax at all: Alaska, Delaware, Montana, New Hampshire, and Oregon. A business operating only in one of those, with no local tax obligations, doesn’t need a sales tax ID. Every other state requires businesses that sell taxable goods or services to register.
Registration is usually free or nearly so. A handful of states charge a small fee or a refundable security deposit. The application goes to the state’s department of revenue and typically asks for your federal EIN, business address, and a description of what you sell. So you generally need the EIN in hand first.
You need a sales tax ID in every state where your business has nexus, which is the legal term for a taxable connection to that state. Nexus used to mean physical presence: a store, a warehouse, an employee. After the Supreme Court’s 2018 decision in South Dakota v. Wayfair, states can also require collection from businesses that cross an economic activity threshold with no physical presence at all. The most common threshold is $100,000 in gross sales into a state during the year. Some states originally paired that with an alternative trigger of 200 separate transactions, but roughly half of those states have since dropped the transaction count. Check the specific state before assuming a single national rule applies.
If you sell through a platform like Amazon, Etsy, or Walmart Marketplace, the platform usually handles collection and remittance on your behalf. Every state with a sales tax has enacted marketplace facilitator laws that shift the collection obligation from the individual seller to the platform. That doesn’t always mean you can skip registration. Some states still require marketplace sellers to register for a sales tax ID even when the platform collects. And direct sales through your own website remain your responsibility.4Streamlined Sales Tax. Marketplace Facilitator State Guidance
Why You Can’t Substitute One for the Other
The two numbers belong to different systems. The EIN is federal. It tracks income owed to the U.S. Treasury and reconciles payroll withholding for Social Security and Medicare. The sales tax ID is state. It tracks consumption taxes owed to a state treasury.
You cannot put your sales tax ID on a federal tax return, W-2, or 1099. You cannot put your EIN on a state sales tax return or hand it to a supplier as proof that you’re authorized to buy goods tax-free for resale. Each number is tied to its own compliance system, its own agency, and its own set of penalties.
They also have different lives. An EIN follows the business entity and mostly stays the same unless the entity’s structure changes, in which case the IRS may require a new one.5Internal Revenue Service. When to Get a New EIN A sales tax ID follows a business’s registration in a particular state, and if the business is sold, the buyer generally cannot continue using the previous owner’s permit and must register fresh.
Which Ones Do You Actually Need?
Most operating businesses need both. If you form a partnership, LLC, or corporation, or hire an employee, the EIN is required from day one. If you sell taxable goods or services in a state that collects sales tax, or you cross that state’s economic nexus threshold from outside, the sales tax ID is required as soon as those sales begin.
A few situations narrow it down. A service-only business in a state that doesn’t tax services may only need the EIN. A sole proprietor with no employees selling only through a marketplace facilitator in a state that doesn’t require separate seller registration might get by without either, using an SSN federally and letting the platform handle sales tax. A retailer with employees carries both numbers from the start.
What Happens if You Use the Wrong Number
Mixing them up creates problems on whichever side you’ve fallen out of compliance with.
Federally, the IRS penalizes businesses that file information returns with a missing or incorrect taxpayer identification number. For returns due in 2026, the penalty is $60 per return if you correct the error within 30 days, $130 if corrected by August 1, and $340 per return if you never fix it. Intentional disregard raises the penalty to $680 per return with no cap.6Internal Revenue Service. Information Return Penalties
On the state side, collecting sales tax without a valid permit can bring civil fines or criminal charges, depending on the state. Penalties escalate with repeat violations, and some states treat each day of unlicensed operation as a separate offense. Even when the correct amount was collected and set aside, operating without the permit can be treated as unlawful collection of public funds.
The more common mistake is smaller: putting the wrong number on a form, which produces processing delays, rejected filings, and follow-up notices. Getting both numbers in place before your first transaction is much cheaper than untangling the paperwork later.