ITIN Number Format and Meaning Explained (2026)

What Is an ITIN and Why Does the IRS Issue Them?

The IRS created the ITIN program in 1996 to solve a specific problem: millions of people in the United States had federal tax obligations but could not get a Social Security Number. Without a taxpayer identification number under IRC Section 6109, they could not file returns, pay taxes, or claim refunds.

Who receives an ITIN

The IRS issues ITINs to non-resident aliens, their spouses, dependents claimed on tax returns, and anyone else who needs to file a U.S. federal return without SSN eligibility. The ITIN application process requires Form W-7, a completed tax return (in most cases), and identity documents from the IRS-approved list of 13 documents.

What an ITIN does and does not do

An ITIN serves one purpose: federal tax processing. It does not authorize employment, prove immigration status, or qualify you for Social Security benefits. Under IRC Section 6103, your ITIN filing information is protected by taxpayer confidentiality. But an ITIN does open doors to banking, credit building, and state-level services in many jurisdictions.

What Does Each Part of the 9XX-XX-XXXX Format Mean?

Every ITIN has 4 distinct segments. Understanding each one helps you verify your number, spot errors on tax forms, and know when renewal is required.

First digit: always 9

The leading 9 is the most important marker. The SSA has never assigned SSNs starting with 9 and has confirmed it never will. This single digit distinguishes every ITIN from every SSN across all IRS systems, bank databases, and tax preparation software.

Second and third digits: the prefix

Combined with the leading 9, these form a 3-digit prefix the IRS uses to allocate and organize ITIN batches. The IRS opens new prefix ranges as demand grows. Over 4.7 million ITINs were issued between 2019 and 2023.

Fourth and fifth digits: the series identifier

The middle pair identifies the ITIN series. Valid ranges are: 70 through 88, 90 through 92, and 94 through 99. Range 93 is reserved for future use. If these digits fall outside valid ranges, the number is not a legitimate ITIN.

Last four digits: the serial number

These make each ITIN unique within its prefix and series combination. They range from 0000 to 9999, working the same way as the last 4 digits of an SSN.

Why Do the Middle Digits Matter Most for ITIN Holders?

The fourth and fifth digits reveal when the IRS issued your ITIN and whether it needs renewal. The IRS has expanded valid middle-digit ranges multiple times since 1996.

Expired middle-digit ranges

ITINs with middle digits from older ranges (70, 71, 72, 73, 74, 75, 76, 77, 78, 79, or 80) that have not appeared on a tax return in 3 consecutive years are now expired. The IRS rejects returns filed with expired ITINs and delays refunds until renewal is complete.

Current valid ranges (2026)

How to renew an expired ITIN

If your ITIN has expired, submit Form W-7 with the "Renewal" box checked. Processing takes 7 to 11 weeks. A Certifying Acceptance Agent can prepare your renewal in 2 to 10 business days and verify documents so you keep your passport. See our ITIN renewal guide for the complete process.

How Can You Tell an ITIN from an SSN by Looking at the Number?

Both numbers are 9 digits in the XXX-XX-XXXX format. Two checks distinguish them instantly. For a full comparison, see our ITIN vs SSN guide.

What Does Your ITIN NOT Mean?

Your ITIN means you have a federal tax processing identifier assigned under IRC Section 6109. It does not grant any of these:

Not work authorization

An ITIN does not grant permission to work. Employers who accept an ITIN for I-9 verification violate federal law. Only an SSN paired with valid work authorization allows legal employment.

Not immigration status proof

Having an ITIN says nothing about your visa type, residency status, or legal presence. The IRS issues ITINs regardless of immigration status.

Not Social Security eligibility

An ITIN does not earn Social Security credits. No retirement, disability, or Medicare eligibility comes through an ITIN. If you later receive an SSN, your ITIN history does not transfer to benefit calculations. See our ITIN and SSN transition guide.

Not a government ID

The CP565 notice is not an identification document. Some states accept ITINs for driver license applications, but the ITIN letter itself has no photo and carries no ID weight.

When Does Your ITIN Expire and How Do You Renew It?

ITINs are not permanent. The IRS deactivates any ITIN not used on a federal return for 3 consecutive tax years. The IRS also runs rolling expiration programs based on middle-digit ranges.

Impact of expiration on tax filing

If your ITIN has expired, the IRS still accepts your return but processes it without certain credits and exemptions. This means delayed refunds and smaller payments until the ITIN is renewed and reactivated.

Renewal methods

Renewal uses the same Form W-7. You can submit by mail to the IRS ITIN Operations center in Austin, Texas, through an IRS Taxpayer Assistance Center, or through a Certifying Acceptance Agent (CAA). A CAA verifies your documents in person so you never mail your passport. Processing takes 7 to 11 weeks by mail.

Checking your ITIN status

Not sure if your ITIN is active? Call 1-800-829-1040 or check your ITIN status through our tracking service.

How Does the IRS Assign ITIN Numbers?

The IRS assigns ITINs sequentially within each available range. The ITIN Operations unit in Austin, Texas reviews every Form W-7, verifies identity documents, and assigns the next available number from the current active range.

Number selection rules

You cannot choose your ITIN, request a specific range, or transfer an ITIN between people. The IRS never reuses an ITIN previously assigned to someone else. Each 9-digit combination is permanently tied to one individual.

Processing timelines by method

Mailing Form W-7 to the IRS takes 7 to 11 weeks. A CAA handles document verification before submission, reducing rejection risk. During peak tax season (January through April), processing stretches toward 11 weeks. Check our ITIN processing time guide for month-by-month estimates.

How Do You Protect Your ITIN from Identity Theft?

Your ITIN carries the same sensitivity as an SSN. If someone obtains your ITIN, they can file fraudulent returns, steal refunds, and create tax liabilities. Follow these 5 rules:

Secure electronic communication

Never share your ITIN over email, text, or social media. Use encrypted channels or in-person communication.

Physical document security

Store your CP565 notice in a locked cabinet or safe deposit box. Keep a digital backup in an encrypted password manager.

Report suspected fraud immediately

Contact the IRS Identity Protection Specialized Unit at 1-800-908-4490. File Form 14039 (Identity Theft Affidavit). The IRS will flag your account and assign an Identity Protection PIN for future filings.

IRC Section 6103 protections

Under Section 6103 of the Internal Revenue Code, your ITIN information and tax filing history are protected by taxpayer confidentiality. The IRS cannot share this data with immigration authorities or other agencies without consent or court order.