EIN vs. TIN vs. SSN vs. ITIN: Which Number Is Which

Last updated September 3, 2026 · Written by the EIN Registration filing team

TIN, taxpayer identification number, is the family name. Every number the IRS uses to identify a taxpayer is a TIN. The members of the family: an SSN identifies a person who is eligible for one; an ITIN identifies a person who is not; an EIN identifies a business, estate, trust or other entity. FEIN and “federal tax ID” are other names for the EIN. When a form asks for your TIN, it is asking for whichever one applies to the taxpayer filling it in.

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The family tree

NumberIdentifiesIssued byFormat
SSNA person eligible for Social SecuritySocial Security Administration3-2-4 digits
ITINA person who must file U.S. taxes but cannot get an SSNIRS, on Form W-73-2-4 digits, starts with 9
EIN (FEIN)A business, estate, trust, nonprofit or planIRS, on Form SS-42-7 digits
ATIN, PTINA child pending adoption; a paid tax preparerIRSSpecialised, rarely relevant

EIN vs. SSN

An SSN belongs to a person; an EIN belongs to an entity. A sole proprietor is a person, so a sole proprietor may use their SSN for the business and is not required to have an EIN, though most get one to keep the SSN off business paperwork. When a sole proprietor needs an EIN. An LLC, corporation, partnership, estate or trust is not a person, and needs an EIN whenever a form asks for the entity’s number.

EIN vs. ITIN

Both are issued by the IRS and both are for taxpayers who cannot use an SSN, which is why they are confused. An ITIN is for an individual; an EIN is for an entity. A foreign founder might have an ITIN for their personal return and an EIN for their U.S. LLC, and the ITIN can be the responsible party’s number on the LLC’s EIN application. EIN with an ITIN.

EIN vs. FEIN vs. tax ID

The same number. “Federal employer identification number” is the full name; FEIN, EIN, federal tax ID and business tax ID all refer to it. The word “employer” is historical; an entity with no employees still gets an EIN. State tax IDs are different: each state issues its own account numbers for sales tax, withholding and so on, and those are not the EIN.

Which number a form is asking for

  • W-9. Either. A sole proprietor gives their SSN or EIN; an entity gives its EIN.
  • W-2 box b. The employer’s EIN.
  • 1099, payer box. The payer’s EIN, or SSN if the payer is a sole proprietor without one.
  • Form 1040. Your SSN or ITIN. Never an EIN.
  • Schedule C. Your SSN at the top; the business’s EIN in its own box if you have one.
  • Business bank account, entity. The EIN.
  • State tax registration. The EIN, and the state then issues its own account number.

Quick answers

Is a TIN the same as an EIN?

An EIN is one kind of TIN. Every EIN is a TIN; not every TIN is an EIN.

Can a business have an SSN?

No. A sole proprietorship uses the owner’s SSN because it is not separate from the owner. Any other business uses an EIN.

Can a person have an EIN?

A person acting as a sole proprietor or household employer can obtain one. It identifies their business activity, not them; their personal return still uses the SSN.

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Related guides

EIN Registration is an independent document preparation and filing service and is not affiliated with the IRS or any government agency. You can also apply for an EIN directly with the IRS at irs.gov at no cost.