I can't get a Social Security number. How do I file US taxes (ITIN)?

Checked on 2026-10-25

Apply for an Individual Taxpayer Identification Number (ITIN): a 9-digit number the IRS issues if you need a taxpayer number for federal tax purposes but aren't eligible for an SSN. Apply on Form W-7 with your tax return attached, by the return's due date. Allow about 7 weeks, or 9-11 weeks in tax season or from abroad.

Key facts

What	IRS guidance says	Source
What an ITIN is	A 9-digit number for federal tax purposes, for people who need a taxpayer identification number but aren’t eligible for an SSN	IRS, ITIN
Who needs one	Anyone with a federal tax purpose (for example, required to file a return, claiming a refund or tax benefit, or claimed as a spouse or dependent) who is not eligible for an SSN	IRS, ITIN: Who needs an ITIN
Who doesn’t	US citizens, green card holders, nonresidents with a US work visa (they qualify for an SSN), and anyone eligible for an SSN	IRS, ITIN: Who doesn’t need an ITIN
What it doesn’t do	No Social Security benefits or Earned Income Tax Credit; no immigration status; no permission to work; no ID outside the federal tax system	IRS, ITIN: What an ITIN is used for
How to apply	Form W-7, by mail or in person, with your tax return in the application package	IRS, ITIN
When	On or before your tax return’s due date	IRS, ITIN: When to apply
Processing	Allow 7 weeks; 9–11 weeks in tax season (January 15 to April 30) or if you applied from overseas	IRS, ITIN: After you apply

Who should apply

The IRS says you can apply regardless of immigration status if you are a resident or nonresident alien, or their spouse or dependent, and you have a federal tax purpose. Examples it gives: a nonresident claiming a treaty benefit or filing a federal return, a resident alien filing a federal return, and a dependent or spouse of a US citizen, resident alien or nonresident visa holder. A spouse or dependent is eligible only if they can be claimed for an allowable tax benefit or file their own return. A return with all zero entries generally shows no federal tax purpose.

Applying with your return

The IRS says you include your tax return in the ITIN application package rather than filing it separately. If you need more time, you can request an extension on Form 4868 without an ITIN, writing “ITIN TO BE REQUESTED” in the SSN/ITIN field; the extension (to October 15) covers filing, not payment. You can also make estimated tax payments without an ITIN the same way.

To claim the child tax credit, the credit for other dependents or the American opportunity tax credit, the IRS says the ITIN must be assigned to you, your spouse (if filing jointly) and your dependent by the return’s due date, including extensions.

If you later get an SSN

You can’t have both. The IRS says to stop using the ITIN, use the SSN for tax purposes, and notify the IRS (by mail or at a local IRS office) so it combines your records under the SSN; otherwise you may not get credit for all wages and withholding.

Whether you are a resident or nonresident for tax purposes depends on the green card and substantial presence tests (see the tax residency page).

Sources

IRS: Individual Taxpayer Identification Number (ITIN) checked 2026-10-25

Change history

2026-10-25: Page created

This is general information, not legal advice, and Lumen is not a law firm. Rules change and offices differ: check the official sources above before you act. Found something wrong or out of date? Write to support@lumen.observer.