What is the format of an ITIN number?

ITINs follow the format 9XX-XX-XXXX. The first digit is always 9, the fourth and fifth digits (group code) fall within ranges the IRS reserves for ITINs, and the final 4 digits are a serial number unique to the holder.

Why does an ITIN start with 9?

The IRS reserves the 9 prefix so software, banks, and tax preparers can identify an ITIN at a glance and apply the correct tax-treatment rules. The Social Security Administration never issues SSNs starting with 9.

Are ITINs and SSNs the same length?

Yes. Both ITINs and SSNs are 9 digits long and use the XXX-XX-XXXX format. The difference is the leading digit (ITINs start with 9; SSNs do not) and the middle group-code range.

Does the ITIN contain any personal information?

No. The 9-digit ITIN is a randomly assigned identifier. It does not encode birth date, country of origin, or visa status. The number simply links an individual to their IRS tax record.

Updated June 25, 2026

How Many Digits Is an ITIN Number? Format and Structure Explained

How Many Digits Are in an ITIN Number Exactly?

An ITIN has exactly 9 digits. There are no letters, no extra characters, and no country code. The number is printed with two hyphens in the format 9XX-XX-XXXX on IRS notices and the CP565 assignment letter.

The length is identical to a Social Security Number, which is why banks, payroll systems, and tax software can accept an ITIN in the same field as an SSN. The difference is only the leading digit and the middle group code.

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

Section	Digits	Meaning
Area	9XX	Always begins with 9 to mark the number as an ITIN
Group	XX	IRS-reserved range (50-65, 70-88, 90-92, 94-99)
Serial	XXXX	Unique 4-digit identifier for the taxpayer

For sample ITINs and how the format appears on documents, see the ITIN number example page.

How Is the ITIN Format Different From a Social Security Number?

Both are 9 digits in the format XXX-XX-XXXX. The differences are structural:

Leading digit: ITINs always start with 9; SSNs never do.
Middle group code: ITINs use IRS-reserved ranges (50-65, 70-88, 90-92, 94-99). SSNs use a different group numbering system.
Issuer: ITINs are issued by the IRS. SSNs are issued by the Social Security Administration.
Purpose: An ITIN is for federal tax reporting only. An SSN authorizes work and Social Security benefits.

Why Is the ITIN Format Useful for Banks and Tax Software?

Because the ITIN is the same length as an SSN, every system that accepts a 9-digit taxpayer ID accepts an ITIN. Tax software auto- detects the 9 prefix and applies non-resident tax rules where relevant. Banks use the format to satisfy Customer Identification Program (CIP) requirements without modifying their KYC pipelines.

For a deeper format breakdown including all valid group code ranges, read the ITIN number format guide.

What Happens If an ITIN Is Written With the Wrong Number of Digits?

A mistyped ITIN with 8 or 10 digits will be rejected by the IRS e-file system, most bank account-opening flows, and payroll software. The most common error is dropping a leading zero from the serial portion. Always confirm the 9-digit count against the CP565 notice before submitting any form.

Where Will You See the ITIN Format on IRS Documents?

The 9-digit format appears on the CP565 assignment notice, on every annual CP-series renewal notice, on Form 1040 in the SSN field, and on W-7 acceptance letters. Tax preparers print the format the same way payroll systems print SSNs.

Frequently Asked Questions About ITIN Digits and Format

An ITIN is exactly 9 digits, formatted as 9XX-XX-XXXX. It uses the same length and format as a Social Security Number, but always begins with the digit 9 to distinguish it.

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