How to Apply for an ITIN With Form W-7 (2026): Documents, Steps, Cost & Timeline

01Who should apply for an ITIN (and who shouldn't)

Apply for an ITIN if you have a U.S. tax reason to file — wages, 1099 income, rental income, a treaty claim, or being claimed as a spouse/dependent — and you're not eligible for a Social Security number. If you can get an SSN, get that instead; you never use both.

In plain terms, that includes international students and scholars with a filing requirement, foreign nationals who earn money from U.S. sources, immigrants who work and pay taxes without work authorization, and the nonresident spouse or children a U.S. taxpayer wants to claim. Who shouldn't apply? Anyone eligible for a Social Security number — most work-authorized visa holders and green-card holders — should get an SSN instead, and anyone with no U.S. tax purpose at all won't qualify.

This guide is the deep-dive on the application itself. For the full picture of filing with an ITIN in 2026 — including which credits changed this year — start with our complete 2026 ITIN filing guide.

02The documents you need for Form W-7

You must prove two things: your identity and your foreign status.

Documents must be originals or copies certified by the issuing agency — photocopies are rejected, which is the #1 reason applications bounce.

03Three ways to submit — and why not to mail your passport

You don't have to put your only passport in the mail. You have three options:

04Filling out Form W-7, line by line (the parts that trip people up)

• Reason for applying — check the box that matches your situation (e.g., nonresident filing a return, dependent/spouse of a U.S. person, treaty claim). The wrong box causes a rejection.
• Name & birth name — must match your supporting documents exactly (same spelling, same order). Mismatches are a top delay.
• Mailing address — where the IRS sends your assignment notice and returns your documents. A P.O. box is allowed.
• Renewing? Put your existing ITIN on line 6f so the IRS matches it to your record — see our ITIN renewal guide for the full steps.

Then attach your federal tax return to the front of the W-7 and submit the package together — the IRS assigns the ITIN first, then processes the return.

05Do you always have to attach a tax return?

In most cases, yes — your Form W-7 rides along with the federal return that creates the need for the ITIN. But the IRS recognizes a handful of exceptions where you can apply without a return attached:

• Passive income with withholding — a bank or broker that must withhold on interest, dividends, or royalties and needs your ITIN for reporting.
• Wages, salary, or scholarship income covered by a tax treaty or specific withholding rules.
• Third-party mortgage interest reporting on a U.S. property.
• Dispositions of U.S. real property subject to withholding.
• Certain reporting obligations under Treasury regulations.

Each exception has its own supporting-document requirements listed in the W-7 instructions. If you don't fit one of them, plan to attach the return — applying "just to have" an ITIN, with no tax purpose, gets rejected.

06When to apply — and how not to miss your refund

Timing matters, because the ITIN has to exist before your return — and any refund — can be processed.

• Apply early. Build in the full 7–11 week processing window. For the 2026 tax year, the filing deadline is April 15, 2027; don't start the application the week before.
• Running late? You can file an extension to protect your filing position while the ITIN is processed. An extension to file isn't an extension to pay — but it keeps you in good standing and preserves your refund claim.
• Renewing? Submit the W-7 renewal before you file the return; filing with an expired ITIN delays the refund and can cause credits to be disallowed.
• Old refunds. You generally have up to three years to claim a federal refund, so if you skipped past years where tax was withheld from your pay, it may still be worth filing them.

07Applying for a spouse or dependent's ITIN

You can apply for ITINs for a spouse or dependents you claim — but the rules tightened after 2017: a spouse or dependent generally needs an ITIN only when they're claimed for an allowable tax benefit, not simply to be listed on the return.

• Everyone files their own Form W-7, each with their own identity and foreign-status documents, submitted together with the family's tax return.
• Dependents can use medical records (under 6) or school records (under 24) as supporting documents, alongside a passport or two of the accepted IDs.
• A dependent living in Mexico or Canada can be claimed, but a dependent has never qualified the family for the Child Tax Credit without the child's own SSN — and in 2026 the taxpayer needs an SSN too (the main guide covers the 2026 credit math in full).

08What it costs

• The IRS charges nothing to issue an ITIN.
• Free help: VITA sites and many nonprofit Certifying Acceptance Agents prepare ITIN applications at no cost.
• Commercial CAAs typically charge about $50–$275 to verify your documents so you don't mail your passport.

Curious what filing could put back in your pocket first? Try the free tax-leak calculator.

09How long it takes — and when your refund shows up

Plan on about 7 weeks for the IRS to process Form W-7, and up to 9–11 weeks during the January–April filing peak. A few notes that surprise people:

• You can't check ITIN status online — the IRS notifies you by mail.
• Your assignment notice and your returned documents arrive separately.
• Your refund follows after the ITIN is issued and the return processes — so apply early, well before the deadline, if you're expecting money back.

10After you get your ITIN

• Keep it active. An ITIN expires if it isn't used on a federal return at least once in three consecutive years — filing every year keeps it alive.
• If you later get an SSN, stop using the ITIN and file under the SSN. You can ask the IRS to combine your prior records under the new number.
• Use it to build. Most banks accept an ITIN to open an account and start a U.S. credit history.

11The mistakes that get W-7s rejected

• Sending photocopies instead of originals or agency-certified copies.
• Name / date-of-birth mismatches between the W-7, your ID, and your return.
• Forgetting to attach the tax return (when you don't qualify for an exception).
• Applying when you're actually eligible for an SSN.
• Filing with an expired ITIN instead of renewing first.

Avoid those and most applications go through on the first try. When you're ready to file, the 2026 ITIN filing guide walks through the return itself and the credits that changed this year, and the Money Moves Guide covers the rest.