US EIN Format Validator

US EIN (Employer Identification Number): the business tax ID

The Employer Identification Number (EIN), also called the Federal Tax Identification Number, is the IRS identifier for businesses and other entities — corporations, partnerships, LLCs, non-profits, estates and trusts. The format is 9 digits written as XX-XXXXXXX (two digits, a hyphen, then seven), e.g. 12-3456789.

The first two digits are the prefix, historically tied to the IRS campus that assigned the number; since 2001, online-issued EINs use prefixes assigned by the internet EIN system regardless of geography. A valid EIN's prefix must be one of the IRS-published values — some prefixes (e.g. 07, 08, 09, 17, 18, 19, 28, 29, 49, 78, 79, 89) are not used. The EIN has no check digit.

EIN vs SSN vs ITIN

• EIN: XX-XXXXXXX — identifies a business/entity. Public for many filers (it appears on W-2s, 1099s, and non-profit Form 990s).
• SSN: XXX-XX-XXXX — identifies an individual. Highly sensitive.
• ITIN: 9XX-XX-XXXX — individuals without SSN eligibility.
• A sole proprietor may use either an SSN or an EIN for the business; an EIN is required once you have employees or form a corporation/partnership.

Common pitfalls

• Hyphen placement: the EIN groups as 2-7, unlike the SSN's 3-2-4. Reformatting an SSN-style group is a classic data-entry error.
• Invalid prefix: a structurally 9-digit number with an unused prefix is not a valid EIN.
• Format ≠ registration: only the IRS (or the SSA's EIN verification) confirms an EIN is real and active; this tool checks structure.

FAQ

How is an EIN formatted? Nine digits as XX-XXXXXXX — two digits, hyphen, seven digits.

Does an EIN expire? No. Once assigned, an EIN belongs to that entity permanently and is never reused, even after the business closes.

Is an EIN confidential like an SSN? Less so — EINs appear on many public documents (e.g. non-profit 990s), but should still be handled carefully to prevent fraud.