SSN vs ITIN: Which One Do You Need as a New Immigrant?
In this guide
Quick answer: A Social Security number (SSN) is for people the US government has authorised to work, while an Individual Taxpayer Identification Number (ITIN) is for people who need to deal with US federal taxes but are not eligible for an SSN. According to the IRS, you cannot have both. If you can get an SSN, that is the number you should use.
Many newcomers to the United States hear both terms in the first few weeks, usually from a bank, a landlord or an employer, and assume they are interchangeable. They are not. They come from different agencies, they serve different purposes, and choosing the wrong route can cost you weeks. This guide explains the difference in plain language, who qualifies for which, and how to apply, using the official guidance from the Social Security Administration (SSA) and the Internal Revenue Service (IRS).
What is the difference between an SSN and an ITIN?
| SSN | ITIN | |
|---|---|---|
| Issued by | Social Security Administration | Internal Revenue Service |
| Who it is for | Generally, non-citizens authorised to work in the US by the Department of Homeland Security (DHS) | People with a federal tax purpose who are not eligible for an SSN |
| Format | 9 digits | 9 digits |
| Authorises work? | Yes, for a standard SSN (a work-authorised holder) | No |
| Cost | Free | Free from the IRS; some agents charge a fee |
The IRS describes the ITIN as a number for federal tax purposes only. It does not give you the right to work, it does not change your immigration status, and it is not identification outside the federal tax system.
Who can get an SSN?
The SSA says that, generally, only non-citizens authorised to work in the US by DHS can get an SSN. A non-citizen who is not work-authorised may get a “nonwork” SSN only for a valid nonwork reason, for example when a federal law requires an SSN to receive a federally funded benefit, or a state or local law requires one for public assistance for someone legally residing in the US. The SSA is clear that if you are assigned an SSN for nonwork purposes, you cannot use it to work.
What documents does the SSA ask for?
- Identity and work status: current US immigration documents plus an unexpired foreign passport. Examples include Form I-551, Form I-94, Form I-766 (Employment Authorization Document) or an admission stamp permitting work.
- F-1 and M-1 students: Form I-20 or a letter from the designated school official.
- J-1 and J-2 visitors: Form DS-2019 or an Employment Authorization Document; J-1 students, interns and visitors also need a sponsor letter authorising employment.
- Age: a foreign birth certificate (or one obtainable within 10 business days), or otherwise an unexpired passport or DHS-issued document.
Documents must be originals or copies certified by the issuing agency. The SSA does not accept photocopies, notarised copies or application receipts. You must provide at least two separate documents, although one document can serve more than one purpose.
How do you apply for an SSN?
- Before you enter the US: if you are immigrating, you can apply through the State Department as part of your immigrant visa application. The card is mailed to the address on that application.
- If you are adjusting status: you can apply with Form I-485 through USCIS. If you do not receive your card within 14 days after receiving your green card, contact the SSA.
- If you are already in the US and lawfully present: start online on the SSA’s “Request a Social Security number for the first time” page, then visit an SSA office or Social Security Card Center with your documents within 45 days.
- If you cannot start online: complete Form SSA-5, then phone to book an appointment.
The SSA recommends waiting 10 days after arriving in the US before applying, which helps it verify your DHS documents. Applying for an SSN and card is free. Do not pay anyone who offers to do it for you; the SSA warns that some businesses charge for services it provides at no cost.
Who needs an ITIN?
You need an ITIN if you have a federal tax purpose and are not eligible for an SSN. The IRS lists federal tax purposes as being required to file a US return, claiming a refund or tax benefit, or being claimed as a spouse or dependent. Resident aliens, nonresident aliens and their spouses or dependents can apply regardless of immigration status. Spouses and dependents qualify only if they can be claimed for a tax benefit or file their own return.
You do not need an ITIN if you are a US citizen, a green card holder, a nonresident alien with a US work visa (who qualifies for an SSN), or anyone else eligible for an SSN.
What an ITIN cannot do
- It does not qualify you for Social Security benefits or the Earned Income Tax Credit.
- It does not provide or change immigration status.
- It does not authorise you to work in the US.
- It does not serve as identification outside the federal tax system.
How do you apply for an ITIN?
- Complete Form W-7, Application for Individual Taxpayer Identification Number. Every person applying, including family members, needs their own form.
- Complete your federal tax return (Form 1040 or 1040-NR), leaving the SSN area blank for each ITIN applicant. Attach the W-7 to the front of the return. The IRS says to include the return in the ITIN package rather than file it separately.
- Add supporting documents proving foreign status and identity, plus proof of US residency for dependents.
- Submit by mail to the IRS ITIN Operation in Austin, Texas, or in person.
In person, you have four options: an IRS Taxpayer Assistance Center with ITIN services (free, can authenticate most documents, US only), a VITA site with ITIN services (free, helps complete the W-7), a Certifying Acceptance Agent (fee varies, can authenticate documents, available in the US and abroad), or an Acceptance Agent (fee varies, reviews and mails your documents). The IRS notes it may take several weeks to get a Taxpayer Assistance Center appointment.
How long does an ITIN take?
The IRS says to allow about 7 weeks. It can take 9 to 11 weeks during tax season (January 15 to April 30) or if you applied from overseas. If you mailed original documents, the IRS returns them to the address on line 2 of your W-7 within 60 days. You will get a notice: CP565 means your ITIN was assigned, CP566 means the IRS needs more information, and CP567 means your application was rejected and you must resubmit.
What if you get an SSN after an ITIN?
Once you receive an SSN, stop using your ITIN and tell the IRS so your records can be combined. The IRS says you cannot hold both numbers.
Which one should you choose?
| Your situation | Likely route |
|---|---|
| You have work authorisation from DHS | Apply for an SSN with the SSA |
| You are a green card holder | SSN (you are eligible, so you do not need an ITIN) |
| You are not work-authorised but must file a US return or are claimed as a dependent | ITIN with the IRS |
| You are the spouse or dependent of a US resident or citizen and not SSN-eligible | ITIN, if you can be claimed for a tax benefit or file your own return |
Your own situation depends on your visa and your tax position, so check the current SSA and IRS pages or speak to a qualified tax professional.
Common mistakes to avoid
- Applying for an ITIN when you are eligible for an SSN.
- Sending a photocopy or notarised copy to the SSA, which does not accept them.
- Filing your tax return separately from your ITIN application instead of attaching it.
- Paying a third party for an SSN, which is free from the SSA.
- Carrying your Social Security card in your wallet. The SSA advises keeping it with your important papers.
FAQ
Can I open a bank account or get a driver’s licence without an SSN?
The SSA says many businesses and agencies will identify you another way if you ask, and that most services, including a driver’s licence, are available without an SSN. Policies differ by provider and state, so ask each one directly.
Can an ITIN holder work legally?
No. The IRS states that an ITIN does not authorise work in the US.
Is an ITIN a way to get immigration status?
No. It does not provide or change immigration status.
Do I pay to apply for an SSN?
No. The SSA provides SSN applications and cards free of charge.
Key takeaways
- An SSN is for people authorised to work; an ITIN is for federal tax purposes only.
- You cannot hold both. If you are eligible for an SSN, use it.
- An SSN is free. An ITIN is free from the IRS, but agents may charge.
- An ITIN takes about 7 weeks, longer in tax season or from overseas.
Related guides
- Your first 90 days in a new country
- How to build credit as a new immigrant in the USA
- How to rent an apartment in the US as a new immigrant
- Documents you need before moving abroad
- How to avoid visa and job offer scams
- The complete moving abroad checklist
This article is general information, not legal or tax advice. Rules and processing times change, so confirm with the SSA and IRS. Last updated: October 2026.
Sources
- Social Security Administration: Social Security Numbers for Noncitizens
- Social Security Administration: Social Security number and card information
- Internal Revenue Service: Individual Taxpayer Identification Number
- Internal Revenue Service: How do I apply for an ITIN?