BEFILING.COM | TAX REFERENCE GUIDE
Updated for Tax Year 2026 | By BeFiling Expert Team | 5 min read
Every U.S. tax return, business filing, and financial application requires a valid tax identification number. But with four different types of IDs — SSN, ITIN, EIN, and ATIN — it can be confusing to understand which number applies to you, what the valid number ranges are, and how to verify whether a number is legitimate. This guide provides a complete, authoritative reference for all U.S. taxpayer identification numbers, their valid ranges, formats, and what to do if your number has expired or been rejected.
| Quick Reference — All U.S. Tax ID Numbers at a Glance This guide covers: • SSN — Social Security Number (U.S. citizens and eligible residents) • ITIN — Individual Taxpayer Identification Number (non-residents & foreign nationals) • EIN — Employer Identification Number (businesses & LLCs) • ATIN — Adoption Taxpayer Identification Number (pending adoptions) • IRSN — IRS Number (temporary IRS-assigned processing number) |
All U.S. Tax ID Numbers — Summary Table
| Number | Format | Who Gets It | Primary Use | Issued By |
| SSN | XXX-XX-XXXX | U.S. Citizens & eligible residents | Work, benefits, taxes | Social Security Administration |
| ITIN | 9XX-XX-XXXX | Non-residents, no SSN eligibility | U.S. tax filing only | IRS (Form W-7) |
| EIN | XX-XXXXXXX | Businesses, LLCs, corporations | Business tax ID, banking | IRS (Form SS-4) |
| ATIN | 9XX-93-XXXX | Adopted children pending SSN | Temporary tax ID for child | IRS (Form W-7A) |
| IRSN | Internal only | IRS assigned temporarily | IRS processing only | IRS (internal) |
1. Social Security Number (SSN)
A Social Security Number (SSN) is a nine-digit number issued by the Social Security Administration (SSA) to U.S. citizens, permanent residents, and certain work-authorized immigrants. It is the primary tax identification number used by the IRS for individual income tax returns.
SSN Format
An SSN is formatted as: AAA-GG-SSSS where:
- AAA = Area Number (first 3 digits) — historically based on the state of application
- GG = Group Number (middle 2 digits)
- SSSS = Serial Number (last 4 digits)
Valid SSN Ranges
| 001-01-0001 through 665-99-9999 667-01-0001 through 899-99-9999 750-01-0001 through 763-99-9999 764-01-0001 through 899-99-9999 |
Invalid / Rejected SSN Patterns
| A tax return will be automatically rejected if the SSN contains: • All zeros in any segment — e.g., 000-XX-XXXX, XXX-00-XXXX, or XXX-XX-0000 • Area Number of 666 — this range is permanently reserved and never issued • Area Numbers 900–999 — reserved for ITINs and ATINs (see below) • Numbers beginning with 8 or 9 followed by specific group patterns • 078-05-1120 — a famous invalid ‘test’ SSN that appears in IRS training documents • 219-09-9999 — another commonly misused test number |
Who Is Eligible for an SSN?
- U.S. citizens (at birth or naturalization)
- Lawful permanent residents (Green Card holders)
- Certain non-immigrant visa holders authorized to work in the U.S. (H-1B, L-1, O-1, etc.)
- F-1 and J-1 students with work authorization (CPT, OPT, or campus employment)
Non-residents who are not eligible for an SSN must apply for an ITIN instead. See Section 2 below.
2. Individual Taxpayer Identification Number (ITIN)
An ITIN is a nine-digit tax processing number issued by the IRS to individuals who are required to have a U.S. taxpayer identification number but are not eligible for a Social Security Number. ITINs are used exclusively for federal tax purposes — they do not authorize work in the U.S. or provide eligibility for Social Security benefits.
ITIN Format
An ITIN always begins with the digit 9 and has a specific format: 9XX-XX-XXXX. The middle two digits (positions 4–5) identify the type and batch of the ITIN and are used to track expiry schedules.
Valid ITIN Ranges
| 900-70-0000 through 999-88-9999 900-90-0000 through 999-92-9999 900-94-0000 through 999-99-9999 |
ITIN Middle Digits — Reserved & Excluded Ranges
Not all middle-digit combinations in the 9XX range are valid ITINs. The following ranges are reserved for other purposes and cannot be valid ITINs:
| 9XX-89-XXXX through 9XX-89-XXXX → Reserved (not issued as ITINs) 9XX-93-XXXX → Reserved for ATIN (Adoption Tax ID) 9XX-93-XXXX → ATIN range only |
ITIN Expiry Schedule — Critical for 2026 Filers
ITINs that have not been used on a federal tax return for three consecutive years automatically expire on December 31 of the third year. In addition, ITINs with specific middle digits have been subject to rolling expiry schedules. Use the table below to check whether your ITIN is still valid:
| ITIN Middle Digits | Expiry Date | Action Required |
| 70, 71, 72, 73, 74 | Expired Dec 31, 2020 | Renew immediately |
| 75, 76, 77, 78, 79 | Expired Dec 31, 2021 | Renew immediately |
| 80 | Expired Dec 31, 2021 | Renew immediately |
| 83, 84, 85, 86, 87 | Expired Dec 31, 2021 | Renew immediately |
| 88 | Expired Dec 31, 2022 | Renew immediately |
| 90, 91, 92, 94, 95 | Expired Dec 31, 2022 | Renew immediately |
| 96, 97 | Expired Dec 31, 2022 | Renew immediately |
| 98, 99 | Expired Dec 31, 2023 | Renew immediately |
| Any — not used 3+ yrs | Expired Dec 31 of 3rd year | Renew before filing taxes |
| All others (active) | Valid — if used regularly | No action needed |
| Is Your ITIN Expired? BeFiling Can Help. If your ITIN has expired or been rejected, BeFiling’s IRS Certified Acceptance Agents can process your ITIN renewal using Form W-7 — no original passport mailing required. 99% approval rate | 100% money-back guarantee | 75+ countries served Renew your ITIN: befiling.com/itin-application | WhatsApp: +1 (406) 607-2216 |
Who Needs an ITIN?
- Non-resident aliens required to file a U.S. federal tax return (Form 1040-NR)
- Foreign nationals who own a U.S. LLC and have U.S.-source income
- Dependents or spouses of U.S. citizens or resident aliens who cannot obtain an SSN
- Dependents or spouses of non-resident alien visa holders
- Non-resident aliens claiming a tax treaty benefit
- Foreign students with U.S. income not eligible for an SSN
What an ITIN Does NOT Do
| Important Limitations of an ITIN • An ITIN does NOT authorize you to work legally in the United States • An ITIN does NOT make you eligible for Social Security benefits • An ITIN cannot be used for immigration purposes or to prove legal status • An ITIN is NOT a substitute for a Social Security Number • An ITIN does NOT change your tax residency or immigration status |
How to Apply for an ITIN
To apply for an ITIN, you must submit IRS Form W-7 along with a certified copy of your passport (or original documents) and a completed tax return. The easiest and safest method is through an IRS Certified Acceptance Agent (CAA) — like BeFiling — which verifies your identity documents remotely, so your original passport never has to leave your hands.
3. Employer Identification Number (EIN)
An EIN (also called a Federal Tax Identification Number or FEIN) is a nine-digit number assigned by the IRS to business entities — including LLCs, corporations, partnerships, sole proprietors, trusts, and estates. Despite the name, you do not need to have employees to require an EIN.
EIN Format
An EIN is formatted as: XX-XXXXXXX — two digits, a hyphen, then seven digits. Example: 47-1234567.
Valid EIN Ranges and Prefixes
The IRS assigns EINs using specific two-digit prefix codes that identify the IRS campus that issued the number. The following prefixes are currently valid:
| Code Range | IRS Processing Location |
|---|---|
| 01, 02 | Andover, MA (IRS Campus) |
| 03 | Atlanta, GA |
| 04, 05 | Austin, TX |
| 06, 16, 17 | Brookhaven, NY |
| 10, 12 | Fresno, CA |
| 20, 26, 27, 45, 46, 47 | Internet / Online Applications |
| 52, 53, 54, 55, 56, 57, 58, 59 | Cincinnati, OH / Memphis, TN |
| 30, 32, 35, 36, 37, 38, 61 | Kansas City, MO |
| 39 | Ogden, UT |
| 65, 66, 72, 74, 75, 76, 77 | Philadelphia, PA |
| 80, 90 | International (Non-Resident / Foreign Applicants) |
| 98, 99 | International (Frequently Assigned to Foreign-Owned LLCs) |
| Non-Resident EIN Note If you are a non-resident forming a U.S. LLC without an SSN or ITIN, your EIN will typically begin with prefix 98 or 99 — these are assigned by the IRS International office to foreign applicants who apply via fax or phone using IRS Form SS-4. |
Invalid EIN Patterns
| 00-XXXXXXX → Invalid — area code 00 is never assigned 07-XXXXXXX → Invalid — not a valid IRS campus prefix 08-XXXXXXX → Invalid 09-XXXXXXX → Invalid XX-0000000 → Invalid — serial section cannot be all zeros |
When Do You Need an EIN?
- All U.S. LLCs — required to open a business bank account and file business taxes
- Multi-member LLCs — required to file Form 1065 (partnership return)
- Foreign-owned single-member LLCs — required to file Form 5472 + Form 1120
- Corporations (C-Corp, S-Corp) — required for all corporate tax filings
- Trusts and estates — required for estate tax and trust income tax filings
- Any entity hiring employees in the United States
- Marketplace sellers — Amazon, eBay, Etsy, Walmart all require an EIN
How Non-Residents Apply for an EIN
Non-residents cannot use the IRS online EIN portal (which requires an SSN or ITIN). Instead, they must apply via fax (IRS: +1 855-641-6935), mail, or international phone (+1 267-941-1099). On IRS Form SS-4, Line 7b should read ‘Foreign’ if you do not have an SSN or ITIN. BeFiling includes EIN obtainment in every LLC formation package.
4. Adoption Taxpayer Identification Number (ATIN)
An ATIN is a temporary nine-digit number issued by the IRS to a child who is in the process of a domestic adoption, where the adopting taxpayers cannot obtain the child’s SSN before the tax return is due. It allows the adopting parents to claim the child as a dependent while the adoption is still pending.
ATIN Format and Valid Range
Like ITINs, ATINs begin with 9 and are nine digits. However, ATINs have a specific middle-digit range that is exclusively reserved:
| 900-93-0000 through 999-93-9999 |
Key Facts About ATINs
- Temporary number — automatically expires 2 years after issuance
- Can be renewed once — for a total maximum validity of 4 years
- Applied for using Form W-7A — different form from the ITIN (Form W-7)
- Only for domestic U.S. adoptions — not issued for international adoptions
- Replaced by SSN once the adoption is finalized and the child receives their Social Security Number
- Cannot be used for employment — like ITINs, ATINs are for tax purposes only
5. IRS Number (IRSN) — Temporary Processing Number
An IRSN (IRS Number) is a temporary nine-digit number assigned internally by the IRS when a tax return is received without a valid SSN or ITIN. It is used strictly for IRS tracking and processing — it is never issued to the taxpayer and has no value outside the IRS’s own systems.
IRSN Format
| 900-00-0000 through 999-00-9999 (approximate internal range) |
What Happens When the IRS Assigns an IRSN
If the IRS receives a tax return without a valid taxpayer ID, they will temporarily assign an IRSN to process the return. However, this is not a valid substitute for an SSN, ITIN, or EIN. The taxpayer will be required to provide a valid identification number before the return can be fully processed, any refund can be issued, or any tax liability can be formally assessed.
| What to Do If Your Return Was Processed With an IRSN If your return was processed under an IRSN, you must: 1. Apply for an ITIN through an IRS Certified Acceptance Agent (CAA) immediately 2. Notify the IRS of your new ITIN and request they link it to the IRSN-processed return 3. BeFiling’s CAA team specializes in exactly this situation — resubmission and IRSN linkage Contact BeFiling: befiling.com/itin-application | WhatsApp: +1 (406) 607-2216 |
6. How to Verify the Validity of a U.S. Tax ID Number
Before submitting a tax return or business filing, it is critical to verify that the tax ID number is valid. The IRS will automatically reject returns with invalid numbers, which can cause significant delays. Here is how to verify each type:
Verifying an SSN
- SSNs can be verified by employers through the Social Security Number Verification Service (SSNVS) at ssa.gov/employer/ssnv.htm
- The SSN must fall within the valid ranges listed in Section 1 of this guide
- Zeros in the Group or Serial section indicate an invalid number
- IRS e-file will automatically reject returns with SSNs in the 900–999 range (ITIN/ATIN territory)
Verifying an ITIN
- A valid ITIN always begins with 9 and has middle digits within the valid ranges above
- Call the IRS ITIN hotline at 1-800-908-9982 to confirm whether a specific ITIN is active
- Check the expiry table (Section 2) — many ITINs have expired and must be renewed
- A certified copy of the IRS ITIN assignment letter (CP-565) is the official verification document
- BeFiling’s CAA team can verify ITIN status as part of the application or renewal process
Verifying an EIN
- EINs can be verified using the IRS EIN verification letter (CP-575 or 147C letter)
- Call the IRS Business & Specialty Tax Line: 1-800-829-4933 to request a 147C verification letter
- The EIN prefix (first two digits) should match a valid IRS campus code (see Section 3)
- EINs beginning with 00, 07, 08, or 09 are invalid and will be rejected
7. Quick Reference — Valid Number Ranges Summary
| SSN | 001-01-0001 to 665-99-9999 667-01-0001 to 899-99-9999 750-01-0001 to 899-99-9999 | Never starts with 000, 666, or 900+ |
| ITIN | 900-70-0000 to 999-88-9999 900-90-0000 to 999-92-9999 900-94-0000 to 999-99-9999 | Always starts with 9. Middle digits 89 and 93 are excluded. |
| EIN | 01-0000000 to 99-9999999 (excluding invalid prefixes) | Format: XX-XXXXXXX. Prefixes 00, 07, 08, 09 are invalid. |
| ATIN | 900-93-0000 to 999-93-9999 | Middle digits must be exactly 93. Temporary — expires in 2 years. |
8. Frequently Asked Questions
Q: How do I know if my ITIN is still valid?
A: Check the middle digits of your ITIN against the expiry table in Section 2. If your ITIN was not used on a tax return for three consecutive years, it has expired. You can also call the IRS ITIN hotline at 1-800-908-9982 to confirm status. If expired, you must renew it using Form W-7 before filing your next return.
Q: Can I use my ITIN instead of an SSN on a credit card or bank account application?
A: Yes — many U.S. banks and credit card issuers (Bank of America, Citi, Capital One, and others) accept an ITIN in place of an SSN on applications. You enter your ITIN in the tax ID field. Some institutions may ask for additional identity verification such as a passport copy.
Q: What is the difference between an EIN and a Tax ID number?
A: They are the same thing. EIN, Federal Tax Identification Number (FEIN), and Tax ID Number all refer to the nine-digit business identifier issued by the IRS in the format XX-XXXXXXX. When a bank or marketplace asks for your ‘Tax ID Number,’ they are asking for your EIN.
Q: Can a non-resident get an EIN without an ITIN or SSN?
A: Yes. Non-residents can apply for an EIN via fax, mail, or international phone without an SSN or ITIN. On Form SS-4 Line 7b, write ‘Foreign.’ The EIN will typically begin with prefix 98 or 99 when issued to a foreign applicant. BeFiling includes EIN obtainment for non-residents in every LLC formation package.
Q: What happens if I file a tax return with an expired ITIN?
A: The IRS will still accept a return filed with an expired ITIN, but it will be processed without any exemptions or credits related to the expired ITIN. More importantly, if you are owed a refund, the IRS will hold it until your ITIN is renewed and updated. To avoid delays and ensure your credits and exemptions are processed correctly, always renew your ITIN before filing.
Q: Does an ITIN expire if I don’t file taxes for three years?
A: Yes. Under IRS rules, an ITIN that has not been included on a U.S. federal tax return for three consecutive tax years will expire on December 31 of the third year. For example, if you did not file in 2022, 2023, or 2024, your ITIN expired on December 31, 2024 and must be renewed before you can file your 2025 tax return.
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Disclaimer: BeFiling Inc. is a private third-party document preparation service. Not affiliated with the IRS or any U.S. government agency. All IRS ranges and rules referenced are based on official IRS guidance current as of 2026. Verify current information at irs.gov.