Tax ID Number Examples: SSN, EIN, ITIN, ATIN, and PTIN

Federal tax ID numbers come in five formats, and once you know what each one looks like you can identify any of them on sight. Here are tax ID number examples for all five: an SSN looks like 078-05-1120, an EIN looks like 12-3456789, an ITIN looks like 912-70-1234, an ATIN uses the same nine-digit layout as an SSN but is issued temporarily for a child in a pending adoption, and a PTIN looks like P01234567. The differences are small but consistent, and the IRS relies on them to sort individual filings from business filings and taxpayers from paid preparers.¹

Social Security Number (SSN)

The SSN is nine digits in three groups separated by hyphens: XXX-XX-XXXX. A fictional example is 078-05-1120. The three groups were originally called the area number, group number, and serial number, with the first three digits tied to the geographic region where the applicant lived.² That geographic meaning is gone. In June 2011 the Social Security Administration switched to randomized assignment, so a new SSN today tells you nothing about where the person lives.³

The SSN is the standard tax identifier for U.S. citizens and for noncitizens authorized to work in the United States. Federal law requires it on individual income tax returns, benefit claims, and most financial documents tied to your identity.¹ A noncitizen who isn’t authorized to work generally won’t qualify for an SSN and will need an ITIN instead.

Employer Identification Number (EIN)

The EIN is also nine digits, but the hyphen sits in a different place: XX-XXXXXXX. A fictional example is 12-3456789. That one shift in hyphen position is how the IRS tells a business filing from a personal return at a glance.⁴

Corporations, partnerships, LLCs, nonprofits, estates, and many trusts all use an EIN on tax filings. A sole proprietor with no employees can often use an SSN instead, but an EIN becomes required the moment the owner hires someone or sets up a qualified retirement plan.⁴ Trusts split along a similar line: a revocable living trust can use the grantor’s SSN while the grantor is alive, while an irrevocable trust generally needs its own EIN because it’s treated as its own taxpaying entity.

Individual Taxpayer Identification Number (ITIN)

An ITIN uses the same visual layout as an SSN — nine digits split as 9XX-XX-XXXX — but two features make it recognizable. It always starts with the digit 9, and the fourth and fifth digits fall within specific assigned ranges: currently 50–65, 70–88, 90–92, and 94–99.⁵ A fictional example is 912-70-1234.

The IRS issues ITINs to people who need to file a U.S. tax return but don’t qualify for an SSN, most often nonresident aliens, resident aliens without work authorization, and their spouses or dependents. An ITIN does not authorize employment in the United States and does not create eligibility for Social Security benefits. It exists so that people without SSNs can meet their federal tax obligations.

ITINs can expire. If yours doesn’t appear on a filed federal tax return for three consecutive years, it expires on December 31 of that third year. Appearing on someone else’s information return, such as a Form 1099 reporting a payment made to you, doesn’t count as use. Only your own filed return keeps the number active.⁶

Adoption Taxpayer Identification Number (ATIN)

An ATIN is a nine-digit number that follows the same general layout as an SSN, issued as a temporary identifier for a child who has been legally placed in a home for adoption but doesn’t yet have an SSN.⁷ It lets adoptive parents claim the child as a dependent while the adoption is still pending, using Form W-7A with documentation of the placement.⁸

The ATIN is strictly temporary. Once the adoption is finalized, the parents get an SSN for the child and notify the IRS, which deactivates the ATIN. If no notification comes within two years, the number deactivates automatically, and the IRS sends a reminder notice at the 18-month mark warning of the coming expiration.⁷

Preparer Tax Identification Number (PTIN)

The PTIN is the outlier. It’s the only tax ID that isn’t purely numeric: a capital letter P followed by eight digits, written as P00000000. A fictional example is P01234567. The leading letter makes a PTIN unmistakable and signals immediately that the number belongs to a paid tax preparer, not to a taxpayer.

Anyone who prepares or helps prepare federal tax returns for compensation must have a valid PTIN before working on a return, and the number must appear on every return the preparer signs.⁹¹ Preparers who leave it off face a penalty of $50 per return, capped at $25,000 in a single calendar year.¹⁰ If you’re hiring someone to prepare your return, any legitimate paid preparer should be able to show you a current PTIN.

Quick Format Comparison

Set the five side by side and the differences are easy to spot:

SSN: 078-05-1120. Nine digits, hyphens after the third and fifth digits.
EIN: 12-3456789. Nine digits, hyphen after the second digit.
ITIN: 912-70-1234. Nine digits, always starts with 9, middle two digits fall in specific ranges.
ATIN: Nine digits in the same visual layout as an SSN, issued temporarily for a child in a pending adoption.
PTIN: P01234567. Letter P plus eight digits, the only alphanumeric tax ID.

Two quick rules cover almost every case. If the hyphen falls after the third digit, you’re looking at an individual identifier: SSN, ITIN, or ATIN. If it falls after the second digit, it’s an EIN, which means a business, estate, or trust. And if the number starts with a letter, it’s a PTIN belonging to a paid preparer.

Getting the format right on a form matters. An SSN entered where an EIN belongs, or a transposed digit anywhere in a nine-digit string, is one of the simplest reasons a return gets rejected or stuck in processing. Checking the layout before you file catches most of those errors in seconds.

1
Office of the Law Revision Counsel. 26 U.S. Code 6109 – Identifying Numbers
2
Social Security Administration. The SSN Numbering Scheme
3
Social Security Administration. Social Security Number Randomization
4
eCFR. 26 CFR 301.6109-1 – Identifying Numbers
5
Internal Revenue Service. 3.21.263 IRS Individual Taxpayer Identification Number (ITIN) Real-Time System
6
Internal Revenue Service. How to Renew an ITIN
7
Internal Revenue Service. Adoption Taxpayer Identification Number
8
Internal Revenue Service. Instructions for Form W-7A Application for Taxpayer Identification Number for Pending U.S. Adoptions
9
Internal Revenue Service. PTIN Requirements for Tax Return Preparers
10
Office of the Law Revision Counsel. 26 U.S. Code 6695 – Other Assessable Penalties With Respect to the Preparation of Tax Returns for Other Persons