ITIN: filing a tax return when your spouse or children don't have an SSN
Your family has moved, you have an SSN, and your spouse or children don't. You still have to file, and everyone on the return needs a tax ID number. For people who can't get an SSN, the IRS issues an ITIN.
What an ITIN is
An ITIN (Individual Taxpayer Identification Number) is a nine-digit number that starts with 9. It's for taxes only. It doesn't authorize work and doesn't replace an SSN.
It's most often needed for:
- a spouse without an SSN, so you can file jointly;
- children without an SSN, when a tax benefit applies to them;
- a person with US income who isn't eligible for an SSN.
Note: the IRS issues an ITIN to a spouse or child only when it's actually needed for the return, such as for joint filing or a credit. It won't issue one "just in case."
How to apply
- Fill in Form W-7 for each family member without an SSN.
- Attach the W-7s to your return (Form 1040), leaving their SSN fields blank.
- Attach documents proving identity and foreign status.
- Mail the package to the IRS in Austin. A return with a first-time ITIN application can't be e-filed.
Documents
A passport is best: it's the only document that works on its own. Dependent children whose passport has no US entry date also need proof of US residence, such as school or medical records.
The IRS accepts only originals or copies certified by the issuing agency. Nobody wants to mail a passport, so there are Certifying Acceptance Agents (CAAs): they check the documents in front of you, hand back the originals and mail the package themselves.
How long it takes
The IRS says to allow about 7 weeks, or 9–11 weeks during tax season (January 15 to April 30) or when applying from abroad. A return with a W-7 takes longer to process, so any refund comes later too.
What an ITIN does and doesn't get you
- A joint return is usually better than filing separately: a $32,200 standard deduction for a couple for 2026 and wider brackets.
- The $2,200 Child Tax Credit requires a child with a work-eligible SSN. Under the new rules the taxpayer also needs an SSN, and on a joint return at least one spouse must have one.
- A child with an ITIN may qualify for the $500 credit for other dependents; that depends on the child's status and is checked case by case.
- The Earned Income Credit isn't available with an ITIN.
An ITIN can expire
If the number isn't used on any federal return for three years in a row, it expires on December 31 of the third year. Renewing takes the same Form W-7 attached to a return.
Common mistakes
- e-filing with zeros instead of a number — the return is rejected;
- sending uncertified photocopies of a passport — the application comes back;
- applying for a child who brings no tax benefit — it's denied.
If some of your family has SSNs and some don't, work out in advance which filing option is better and who actually needs an ITIN. I prepare the return together with the W-7s.
Sources: IRS: How do I apply for an ITIN, Instructions for Form W-7, Publication 1915, IRS: Child Tax Credit. Checked October 26, 2026.