Definition
A nine-digit tax number from the IRS for people who must file or be listed on a U.S. tax return but cannot get a Social Security number.
What it means
An ITIN is issued by the IRS so people who are not eligible for a Social Security number can meet their tax obligations. It always begins with the number 9. You apply with Form W-7, usually attached to a federal tax return, along with original or certified identity documents such as a passport; some IRS Taxpayer Assistance Centers and certified acceptance agents can verify documents so you keep your originals. An ITIN is for tax purposes only: it does not give permission to work, change immigration status or qualify you for Social Security benefits, and some credits require an SSN. An ITIN expires if it is not used on a federal return for three consecutive tax years. Some banks accept an ITIN to open an account or apply for credit.
Example
A spouse without an SSN who will be listed on a joint return applies for an ITIN with Form W-7 attached to that return; the couple can then file jointly and use the $32,200 standard deduction for 2026.
Illustrative numbers only. Your situation will differ.