TIN vs EIN: Key Differences and When You Need Each

A Taxpayer Identification Number (TIN) is the umbrella category the IRS uses for every kind of tax ID, and an Employer Identification Number (EIN) is one specific type that sits under that umbrella. So the TIN vs EIN comparison isn’t really a choice between two parallel things. Every EIN is a TIN. Not every TIN is an EIN. Once you see the relationship that way, the question usually becomes simpler: which type of TIN do you actually need?

What a TIN Is

A Taxpayer Identification Number is a nine-digit identifier the IRS uses to track individuals and entities for tax purposes.¹ Federal law requires you to put a TIN on tax returns, W-2s, 1099s, and other documents you file or receive.²

The IRS recognizes five types of TIN:

Social Security Number (SSN), issued by the Social Security Administration to U.S. citizens and certain noncitizens. This is the most common TIN and the one most people use for employment, tax filing, and opening bank accounts.³
Employer Identification Number (EIN), issued by the IRS to businesses, nonprofits, estates, trusts, and other entities.
Individual Taxpayer Identification Number (ITIN), issued by the IRS to people who need to file a federal return but aren’t eligible for an SSN. An ITIN doesn’t authorize work in the United States and doesn’t create eligibility for Social Security benefits.⁴
Adoption Taxpayer Identification Number (ATIN), a temporary number the IRS assigns to a child in the process of being adopted so adoptive parents can claim the child before the SSN comes through.
Preparer Tax Identification Number (PTIN), issued by the IRS to anyone who prepares federal tax returns for compensation. A PTIN is eight digits preceded by the letter “P” rather than a standard nine-digit format.

So when someone says “TIN,” they could be talking about any of these. When someone says “SSN” or “EIN,” they’re naming a specific one.

What an EIN Is

An EIN is a nine-digit number the IRS assigns to a business or other entity for tax purposes.⁵ It functions as a Social Security Number for the entity. The format is distinct: an EIN is written XX-XXXXXXX, while an SSN is written XXX-XX-XXXX, so you can tell them apart on sight.⁶ Businesses use their EIN to file tax returns, report employee wages, open bank accounts, and apply for licenses.⁷

How TINs and EINs Differ in Practice

Because the EIN is one branch of the TIN family, most of the “differences” people are looking for are really differences between an EIN and the personal TINs, meaning the SSN and the ITIN.

Who gets one: individuals receive SSNs or ITINs; businesses, nonprofits, estates, and trusts receive EINs.¹
Who issues it: the Social Security Administration issues SSNs. The IRS issues everything else, including EINs, ITINs, ATINs, and PTINs.¹
Format: SSNs follow XXX-XX-XXXX. EINs follow XX-XXXXXXX. ITINs follow the SSN format but always begin with a 9.
Expiration: SSNs and EINs never expire. An ITIN expires if it isn’t used on a federal return for three consecutive tax years.⁸

When You Need a Personal TIN

You need an SSN or ITIN any time you deal with the federal tax system as an individual. Common situations:

Filing a federal income tax return
Starting a job, since your employer needs your SSN for wage reporting
Opening a personal bank account
Claiming dependents on your tax return; each dependent needs a TIN of their own¹
Claiming tax treaty benefits as a foreign individual⁹

If you’re a nonresident or resident alien who isn’t eligible for an SSN but has a U.S. federal tax filing obligation, you use an ITIN instead.⁴ A narrow exception applies to foreign individuals receiving income from marketable securities, who can claim treaty benefits on Form W-8BEN without a U.S. TIN.⁹

When You Need an EIN

The IRS requires an EIN if any of the following is true:⁷

You have employees
You operate as a corporation, partnership, or LLC
You withhold taxes on income paid to a nonresident alien
You file employment, excise, or alcohol, tobacco, and firearms tax returns
You run a nonprofit organization, estate, trust, or retirement plan

Even when federal tax rules don’t require one, you can still request an EIN for banking or state tax reasons.⁷

Sole Proprietors and Freelancers

This is where the TIN vs EIN question gets muddiest. If you’re a sole proprietor with no employees and no excise tax obligations, you can legally use your SSN for all federal tax purposes. You don’t need an EIN. Many freelancers and independent contractors still get one, though, because every W-9 you hand a client puts your tax ID in someone else’s filing cabinet. Using an EIN on that form keeps your SSN out of circulation and lowers your identity theft exposure.

Single-Member LLCs

A single-member LLC with no employees and no excise tax liability doesn’t technically need its own EIN for federal income tax purposes. The IRS treats it as a “disregarded entity” and looks through to the owner’s SSN or EIN.¹⁰ The moment a single-member LLC hires an employee, it has to get its own EIN and use that EIN for all employment tax reporting. In practice, most single-member LLCs end up with an EIN anyway, because banks and state agencies ask for one.

How to Apply

The application process depends on which type of number you need.

SSN

You apply through the Social Security Administration using Form SS-5.¹¹ If you’re in the United States, you can start online and then visit a local SSA office with your documents, or submit everything by mail.³ After approval, your card typically arrives within 7 to 10 business days. Mail-in applications can take another two to four weeks to process before that clock starts.¹²

ITIN

Submit Form W-7 to the IRS by mail, in person at a Taxpayer Assistance Center, or through an IRS-authorized Acceptance Agent.¹³ Paper processing can run several months. As of early 2026, the IRS was processing Form W-7 applications received in February 2026.¹⁴ Build extra time in during peak filing season.

EIN

The IRS offers four ways to apply, all based on Form SS-4:¹⁵

Online, the fastest option. You answer questions through the IRS’s online tool (the “EIN Assistant”) and receive your EIN immediately on approval. Available only if your principal place of business is in the United States or U.S. territories.¹⁶
Fax. Complete a paper Form SS-4 and fax it in. You’ll usually get your EIN within five business days.¹⁴
Mail. Send the completed Form SS-4. Allow about 30 days.¹⁴
Phone, available only to international applicants with no U.S. principal place of business. Call 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern time.¹⁵

The IRS Charges Nothing for an EIN

Getting an EIN is free. Third-party websites that mimic the look of the IRS site and charge up to $300 for an EIN “filing service” have drawn enforcement warnings from the Federal Trade Commission.¹⁷ If you’re applying online, confirm you’re on irs.gov and not a lookalike domain.

1
Internal Revenue Service. Taxpayer Identification Numbers (TIN)
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Office of the Law Revision Counsel. 26 USC 6109 – Identifying Numbers
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Social Security Administration. Request a Social Security Number for the First Time
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Internal Revenue Service. Individual Taxpayer Identification Number (ITIN)
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Internal Revenue Service. Valid EINs
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Internal Revenue Service. Understanding Your EIN
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Internal Revenue Service. Employer Identification Number
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Internal Revenue Service. How to Renew an ITIN
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Internal Revenue Service. U.S. Taxpayer Identification Number Requirement
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Internal Revenue Service. Single Member Limited Liability Companies
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Social Security Administration. Application for Social Security Card Form SS-5
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Social Security Administration. How Long Will It Take to Get a Social Security Card
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Internal Revenue Service. About Form W-7, Application for IRS Individual Taxpayer Identification Number
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Internal Revenue Service. Processing Status for Tax Forms
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Internal Revenue Service. Instructions for Form SS-4
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Internal Revenue Service. Get an Employer Identification Number
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Federal Trade Commission. FTC Warns Operators of Websites That Charge for an Employer Identification Number and Claim Affiliation With the IRS