ITIN or SSN: Which Tax ID You Need and How to Apply Before the April 15 Deadline

The April 15, 2026, tax deadline requires immigrants to use an SSN or apply for an ITIN. Payments are due by April even if a filing extension is requested.

Key Takeaways
  • The federal tax filing deadline for 2025 returns is April 15, 2026 for most taxpayers.
  • Taxpayers must determine eligibility for an SSN or apply for an ITIN using Form W-7.
  • Missing the deadline triggers penalties of 5% per month on unpaid federal income taxes.

(U.S.) — The April 15 Deadline is two weeks away for most taxpayers who must file a 2025 federal tax return, and many immigrants still need to sort out whether they should use an SSN or apply for an ITIN first.

This deadline applies to 2025 tax returns filed in 2026. It does not apply to tax year 2026 returns, which will be filed in 2027.

ITIN or SSN: Which Tax ID You Need and How to Apply Before the April 15 Deadline
ITIN or SSN: Which Tax ID You Need and How to Apply Before the April 15 Deadline

For immigrants, visa holders, and mixed-status families, the first question is simple. Use an SSN if you are eligible. If you are not eligible for an SSN but still must file a U.S. tax return, you may need an ITIN instead.

By law, you cannot have both an SSN and an ITIN. An ITIN is for tax reporting only. It does not authorize work. It does not provide immigration status. It does not serve as a general identification document. The IRS covers these rules in Form W-7 instructions and Publication 519, U.S. Tax Guide for Aliens.

? Deadline Alert: For most individuals, the April 15, 2026 filing deadline applies to 2025 federal returns. An extension can move the filing date to October 15, 2026, but any tax due should still be paid by April 15.

April 15 deadline summary

Tax Event Deadline Extension Available
2025 federal income tax return April 15, 2026 October 15, 2026
2025 balance due payment April 15, 2026 No extra time to pay
ITIN application with return, using Form W-7 On or before April 15, 2026 Can be submitted with extended return
FBAR for 2025 foreign accounts April 15, 2026 Automatic to October 15, 2026

SSN vs ITIN: the main difference

The Social Security Administration issues an SSN. The IRS issues an ITIN.

ID Type Issued By Who Usually Needs It Main Use Limitation
SSN Social Security Administration U.S. citizens, green card holders, and people authorized to work Tax filing, employment, Social Security records, some benefits Required for wages and work compensation
ITIN IRS People not eligible for an SSN but required to file Federal tax returns and related reporting No work authorization; tax use only

If you worked in the United States and were authorized to work, you generally need an SSN, not an ITIN. This is common for H-1B, L-1, O-1, and many employment-based visa holders.

If you are filing Form 1040-NR as a nonresident and cannot get an SSN, you may need an ITIN. The same is often true for a spouse or dependent listed on a return.

Some students and scholars on F-1 or J-1 status file only Form 8843 when they had no U.S. income. In that case, no SSN or ITIN may be required.

Who should act before April 15

You likely need an SSN before filing if you:

  • Worked in the U.S. in 2025
  • Received wages or taxable compensation
  • Are eligible to apply through the Social Security Administration

You likely need an ITIN before or with filing if you:

  • Must file Form 1040-NR
  • Are a resident alien for tax purposes but cannot get an SSN
  • Are a spouse or dependent included on a return and need a tax ID

This point matters for documentation. A valid passport is one of the strongest identity documents for Form W-7. The IRS generally requires original documents or certified copies from the issuing agency. Notarized copies are not enough.

⚠️ Warning: Missing the April 15 Deadline can trigger a failure-to-file penalty of 5% per month, up to 25% of unpaid tax. The failure-to-pay penalty is usually 0.5% per month, up to 25%, plus interest.

How to apply for an ITIN with Form W-7

The IRS says you should apply for an ITIN on or before the return due date and usually attach Form W-7 to the tax return. Do not send a separate W-7 unless an exception applies.

The basic steps are:

  1. Complete Form W-7
  2. Attach your federal tax return, such as Form 1040-NR
  3. Include identity and foreign status documents
  4. Submit by mail, in person, or through an acceptance agent

The normal processing time is about 7 weeks. During peak season, or when applying from overseas, it can take 9 to 11 weeks.

If you mail original documents, keep copies for your records. The IRS says original documents are generally returned within 60 days.

Where to submit the ITIN application

You can submit Form W-7 in several ways:

  • Mail: IRS ITIN Operation, P.O. Box 149342, Austin, TX 78714-9342
  • In person: An IRS Taxpayer Assistance Center that handles ITIN documents
  • Through an AA or CAA: An Acceptance Agent or Certified Acceptance Agent
  • With your tax filing: This is the most common method

If your ITIN has expired, the renewal also uses Form W-7.

Extensions and special deadline relief

If you cannot file by April 15, request an automatic extension on Form 4868. That moves the filing deadline to October 15, 2026.

An extension gives you more time to file, not more time to pay. Estimate and pay what you owe by April 15.

The IRS also sometimes grants extra time to taxpayers in federally declared disaster areas. Check IRS.gov/newsroom for current relief notices if you were affected by a storm, wildfire, or other disaster.

? Tax Tip: Apply early if you need an ITIN and expect a refund, treaty claim, or dependent-related tax benefit. Delays in ID processing can delay the entire return.

Before April 15, gather these items:

  • Your immigration documents
  • Your passport or certified identity documents
  • Wage forms such as Form W-2 or 1042-S
  • Any prior ITIN or SSN records
  • Foreign income and account records, if required

If your status changed during the year, such as F-1 to H-1B, your filing status may be more complicated. Publication 519 covers dual-status issues, residency tests, and treaty rules.

⚠️ Disclaimer: This article is for informational purposes only and does not constitute tax, legal, or financial advice. Tax situations vary based on individual circumstances. Consult a qualified tax professional or CPA for guidance specific to your situation.

People also ask

Answers from VisaVerge guides
What should immigrants do before the 2026 tax filing deadline?

Before January 26, 2026, immigrants should gather their tax forms, create or verify their IRS online account, and choose their filing method to prevent delays.

Read: IRS Tax Season Opens Jan 26, 2026: How to Prepare Now
Who must file Form 1040-NR by April 15, 2025?

Nonresident aliens who were employees with wages subject to U.S. withholding or those who had an office or place of business in the United States must file by this date.

Read: Filing 1040-NR for Calendar Year: April 15 or June 15 Deadlines
What issues can arise with ITIN filings for nonresident taxpayers?

Refund problems can occur when the ITIN application was filed with the return, the number expired, it was entered incorrectly, or spouse or dependent ITIN details do not match IRS records.

Read: Visa Holders and Nris Face IRS Refund Delays as Form 1040-NR, ITIN, Treaty Claims Stall
What is the main federal tax filing deadline for most U.S. residents and visa holders in 2026?

The main federal tax filing deadline is April 15, 2026, for most U.S. residents and visa holders.

Read: IRS Says Average Tax Refund Hit $3,571, a 10.9% Increase as Direct Deposit Refunds Rise
What is the impact of these court rulings on ITIN filers' tax filing process in 2026?

ITIN filers can approach their 2026 tax filings with stronger legal privacy protections, knowing that IRS data sharing for immigration enforcement has been blocked.

Read: IRS and ICE Expand Data Sharing Under Memorandum of Understanding in 2026
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Sai Sankar

Sai Sankar is a law postgraduate with over 30 years of experience across direct and indirect taxation, spanning consultancy, litigation, and policy interpretation. At VisaVerge.com he leads coverage of cross-border finance for immigrants and NRIs — U.S. and state income tax, IRS rules, tariffs and trade duties, foreign-asset reporting, gift and estate tax, and retirement accounts like IRAs and RMDs. Sai's legal acumen turns the tangled intersection of immigration and money into clear, actionable guidance for a global audience.

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