United States Taxpayer Identification Number Guide
The Taxpayer Identification Number (TIN) is the umbrella term for all US tax identifiers. The five types are: Social Security Number (SSN), Employer Identification Number (EIN), Individual Taxpayer Identification Number (ITIN), Adoption Taxpayer Identification Number (ATIN), and Preparer Tax Identification Number (PTIN).
US Tax Identifier Comparison
| Identifier | Issued By | Format | Who Receives It | Primary Use |
|---|---|---|---|---|
| SSN | SSA | NNN-NN-NNNN | US citizens, permanent residents, eligible workers | Income tracking, Social Security, identity |
| EIN | IRS | NN-NNNNNNN | Businesses, trusts, estates, nonprofits | Business tax filing, employer payroll |
| ITIN | IRS | 9NN-NN-NNNN | Non-US persons with US tax obligations | Federal tax filing only |
| ATIN | IRS | 9NN-NN-NNNN | Pending adoptions | Temporary child tax credit |
| PTIN | IRS | P######## | Paid tax preparers | Sign tax returns for clients |
Social Security Number (SSN)
The Social Security Number (SSN) is issued by the Social Security Administration (SSA). It tracks wages and income within the Social Security program and serves as the primary individual identifier for US citizens, permanent residents, and eligible temporary workers.
Format of the SSN
The SSN is a 9-digit number in three parts:
123-45-6789
| Regex | Example |
|---|---|
^(?!9\d{2})\d{3}-\d{2}-\d{4}$ | 123-45-6789 |
Breaking down the SSN
-
123 — Area number (first 3 digits). Before June 2011, assigned geographically by ZIP code. Since June 2011, SSNs are randomized — area numbers no longer reflect geography. The 9XX range is reserved for ITINs and ATINs and is never a valid SSN area number.
-
45 — Group number (digits 4–5). Ranges 01–99. Issued in the order: odd 01–09, even 10–98, even 02–08, odd 11–99.
-
6789 — Serial number (last 4 digits). Sequential 0001–9999 within each area + group combination.
Individual Taxpayer Identification Number (ITIN)
The IRS issues ITINs to individuals who have US tax filing or reporting obligations but are not eligible for an SSN — regardless of immigration status. Common recipients: non-resident alien students and scholars, spouses and dependents of non-resident aliens, foreign nationals receiving US-source income.
Format of the ITIN
The ITIN is a 9-digit number always beginning with 9:
912-53-6789
| Regex | Example |
|---|---|
^9\d{2}-(?:5[0-9]|6[0-5]|7[0-9]|8[0-8]|9[02]|9[4-9])\-\d{4}$ | 912-53-6789 |
Breaking down the ITIN
- Digit 1: Always 9
- Digits 4–5 (middle group): Restricted allocation ranges — 50–65, 70–88, 90–92, 94–99
- All other positions: any digit 0–9
ITIN expiration: ITINs not used on a US federal return for 3 consecutive years expire. Expired ITINs must be renewed via Form W-7 before they can be used again.
Employer Identification Number (EIN)
The IRS issues EINs to businesses, corporations, partnerships, LLCs, estates, trusts, and certain other entities for tax filing and employer identification. A US EIN is not a VAT number — the US has no federal VAT.
Format of the EIN
The EIN is a 9-digit number in two parts:
12-3456789
| Regex | Example |
|---|---|
^\d{2}-\d{7}$ | 12-3456789 |
Breaking down the EIN
- 12 — Prefix (2 digits): identifies the IRS campus or online application that issued the EIN. Certain prefixes are associated with specific IRS service centers.
- 3456789 — Sequence (7 digits): sequential serial number.
Apply for an EIN free at IRS.gov using Form SS-4. Online applications take approximately 10 minutes and the EIN is issued immediately. Foreign entities without a US SSN responsible party must apply by fax or mail.
Adoption Taxpayer Identification Number (ATIN)
The IRS issues ATINs to adoptive parents for a child placed in their home domestically whose SSN cannot yet be obtained. The ATIN is temporary — once the adoption is finalized and the SSN is issued, the ATIN is retired.
Format of the ATIN
The ATIN follows the same 9-digit format as the ITIN (beginning with 9):
| Regex | Example |
|---|---|
^9\d{2}-\d{2}-\d{4}$ | 968-12-3456 |
ATINs are applied for using Form W-7A and are valid for 2 years (extendable once). ATINs cannot be used for Form I-9 employment eligibility.
Preparer Tax Identification Number (PTIN)
The IRS requires all paid tax preparers who prepare or assist in preparing federal tax returns to register and obtain a PTIN. PTINs must be renewed annually.
Format of the PTIN
| Regex | Example |
|---|---|
^P\d{8}$ | P12345678 |
A PTIN beginning with P followed by 8 digits. PTINs are publicly searchable via the IRS Directory of Federal Tax Return Preparers at irs.gov/taxpros/directory.
US Sales Tax Note
The United States has no federal VAT or GST. Sales tax is administered at the state and local level — 45 states plus Washington DC impose sales tax, with rates ranging from 2.9% (Colorado) to 7.25% (California state rate) before local additions. There is no single US sales tax registration number analogous to a VAT number. For multi-state sellers, each state requires a separate registration. For more details, see our US Sales Tax Guides.
Verify a US EIN
To verify an EIN, see the EIN verification guide.
For more details on US tax compliance, see our United States Country Guide.
Frequently Asked Questions
A vendor gave me a 9-starting SSN on their W-9 — is it valid for employment verification?
No. Any SSN beginning with 9 is an ITIN or ATIN — never a valid SSN. The 9XX area number range has always been excluded from SSN allocation. A 9XX number on Form I-9 is invalid for employment eligibility verification. For W-9 (1099 contractor) purposes, a 9XX number indicates an ITIN — valid for tax reporting but potentially triggering Chapter 3 withholding obligations if the individual is a non-resident alien. [1]
My contractor's ITIN has middle digits outside the published ranges — is it still valid?
ITINs issued before 2013 may have middle digits outside the currently published ranges — this alone does not make them invalid. However, the IRS ITIN expiration program has retired many older ITINs: ITINs unused for 3 consecutive years expire; ITINs with middle digits 70–88, 90–92, and 94–99 issued before 2013 expired after 31 December 2020 unless renewed. Verify currency via IRS e-Services TIN Matching; if a mismatch occurs, ask the contractor to renew via Form W-7. [1]
Can someone use an ITIN to open a US bank account or apply for credit?
An ITIN is issued solely for tax purposes and confers no work authorization or Social Security eligibility. Bank and credit card policies vary: many major banks accept ITINs for account opening under their CIP programs; some community banks and credit unions specifically serve ITIN holders. Some institutions still require an SSN. ITIN holders cannot contribute to Social Security or Medicare. [1]
Single-member LLC — use my SSN or get an EIN?
A single-member LLC is a disregarded entity by default — you report on Schedule C using your SSN. However, you must obtain an EIN if the LLC has employees or files excise tax returns, and banks almost always require an EIN to open a business account. An EIN for an SMLLC does not change its tax classification. Apply free via IRS.gov Form SS-4 (online: ~10 minutes, EIN issued immediately). [1]
I lost my EIN — how do I recover it without calling the IRS?
Check: (1) the original IRS CP 575 letter mailed when the EIN was issued; (2) previously filed tax returns (Form 1120, 1065, 941, 940) — the EIN appears on all returns; (3) bank account opening documents; (4) state business filings. If none are available, call the IRS Business & Specialty Tax Line at 800-829-4933 (weekdays 7am–7pm local time) — after identity verification they can provide the EIN and issue a 147C letter (EIN verification letter) by fax on request. [1]
My contractor's W-9 shows an ITIN — can I still issue them a 1099-NEC?
Yes. An ITIN on a W-9 is valid for 1099-NEC reporting. However, if the contractor is a non-resident alien, US-source payments may be subject to Chapter 3 withholding (typically 30%, reducible by tax treaty) — in which case file Form 1042-S instead of or alongside the 1099-NEC. If TIN Matching returns a mismatch, the ITIN may be expired. Backup withholding (24%) applies if the TIN is invalid or the contractor fails to certify on the W-9. [1] [2]
My foreign company needs to withhold US taxes — how do we get a US EIN without a US presence?
Foreign entities cannot use the IRS online EIN application (which requires a responsible party with a US SSN). Instead: complete Form SS-4 and fax it to +1 267-941-1099 (IRS international fax line) or mail it using the international applicant address in the Form SS-4 instructions. Processing takes 4–8 weeks. An EIN is required to file Form 1042 (annual withholding return) and Form 1042-S (payment statements). File Form W-8BEN-E to certify treaty eligibility and reduce withholding rates where applicable. [1]
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