What Is a Business Entity Number? State ID vs. EIN Explained

The number is the state registry's own internal reference for a specific filing — it ties together an entity's formation record, its registered agent information, its filing history, and every amendment or annual report filed afterward. When you search for a company on a state's business entity search (or on this site's state-by-state directory), the entity number is usually the first thing displayed, because it's the fastest, least ambiguous way to pull up an exact record — company names alone can be shared by multiple entities or spelled differently across filings.

It's purely an administrative bookkeeping number. It doesn't reflect the company's size, tax status, or standing — an entity in good standing and one that's been administratively dissolved keep the same entity number for as long as the record exists in that state's system.

An EIN (Employer Identification Number) is issued by the IRS for federal tax purposes and follows the same nine-digit format (XX-XXXXXXX) no matter which state a business is in. An entity number is issued by a state government for its own business registry and has nothing to do with federal taxes — its format, length, and even what it's called varies by state.

Most active LLCs and corporations end up with both, because they serve different purposes: the EIN is what you give a bank or use to file federal taxes, while the entity number is what identifies the filing on the state's books and is what you'd reference when filing an annual report, requesting a certificate of good standing, or amending the entity's formation documents with that state.

Some states' revenue departments also issue a separate state tax ID that's different from both the EIN and the Secretary of State's entity number — a business can genuinely end up juggling three distinct numbers for three different agencies, which is exactly why mixing them up is so common.

There's no standardized national term, which is a big part of why this trips people up. A few confirmed examples: Delaware calls it a File Number. Florida calls it a Document Number. Illinois calls it a File Number. New York calls it a DOS ID number. California's Secretary of State calls it an Entity Number on Bizfile search results, while the state's Franchise Tax Board separately refers to an Entity ID or California Corporation Number on tax forms — two agencies, two labels, for numbers that can actually differ.

A few states make it more layered still. Nevada assigns both an Entity Number and a separate NV Business Identification Number, and its own business search lets you look up an entity by either one. Texas splits it by agency entirely: the Secretary of State issues a File Number (6 to 10 digits) to register the entity, while the Texas Comptroller separately assigns an 11-digit Taxpayer Number for state franchise tax — they're not interchangeable, and a form asking for one won't accept the other. Washington goes a different direction with a Unified Business Identifier (UBI) Number, which — unlike most states' entity numbers — is meant to be used across multiple state agencies, not just the Secretary of State.

This site's state-by-state business entity search pages show each state's actual current numbering system and terminology directly from the source, rather than assuming every state works the way one familiar state does.

The most reliable place is the approval letter, stamped certificate, or filed copy of your Articles of Organization or Articles of Incorporation that the state sent back after formation — the number is typically printed at the top or in the state's standard approval language. It also appears on any later correspondence from the state, like an annual report reminder or a certificate of good standing.

If you've misplaced those documents, the free business entity search on the state's own website (or this site's directory of state search pages) will show it once you look up the company by name — no account or fee required in any state.

Is an entity number the same as an EIN?

No. An EIN is a federal tax ID issued by the IRS in the same format nationwide; an entity number is issued by the state where the business is registered, and its format and name vary by state. Most active businesses have both, for different purposes.

What if my state doesn't call it an "entity number"?

That's normal — terminology varies widely. Delaware and Illinois use "File Number," Florida uses "Document Number," New York uses "DOS ID number," and a few states, like Texas and Nevada, maintain more than one differently named number across different agencies. Whatever it's called in your state, it functions the same way: a unique ID tied to your entity's state filing.

Do sole proprietorships have an entity number?

Generally no. Entity numbers are assigned to formally registered entities — LLCs, corporations, and similar structures filed with the state. A sole proprietorship that hasn't filed a formation document with the state typically isn't in that registry and has no entity number, though filing a DBA/fictitious name in some states can create a separate registration record.

I have two different numbers for my business — which one do I use?

Use whichever number the specific form or agency is asking for. States like Texas and Nevada intentionally maintain separate numbers for separate purposes (state entity registration vs. state tax accounts), so the right one depends on who's requesting it, not on which number you find first.