What is an ITIN vs SSN
Published on October 27, 2025
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What is an ITIN vs SSN?
An ITIN and an SSN are both US tax identification numbers, but they serve different groups. An SSN is for US citizens and authorized workers, while an ITIN is for individuals, often expats or foreign residents, who must file US taxes but don’t qualify for an SSN.
If you’re living abroad, this can become particularly challenging. You might already have a local tax ID or residency number, but you’ll still need a US identification in order to file your US tax returns. The key is figuring out which one applies to your situation and why it matters.
What is an SSN (Social Security Number), and who actually needs one abroad?
An SSN is a nine-digit number issued by the Social Security Administration (SSA). In the US, it’s the key to almost everything: employment, Social Security benefits, credit history, and tax filing.
You qualify for an SSN if you’re a:
- US citizen
- Green Card holder or
- Visa holder authorized to work in the US
For expats, your SSN doesn’t expire or disappear just because you move overseas. You’ll still use it when filing your US tax return (Form 1040) each year, even if you also pay taxes in the country where you live.
2025 update: The SSA has rolled out digital SSN access and stronger identity-proofing requirements. That means applying or replacing a card often involves an online verification step, even for those living outside the US.
What is an ITIN (Individual Taxpayer Identification Number) and who needs it most?
An ITIN is also a nine-digit number, but it’s issued by the IRS rather than the SSA. It always starts with the number 9. You’ll need an ITIN if you’re not eligible for an SSN but still have to file U.S. taxes. Common examples include:
- Nonresident aliens earning US income
- Foreign spouses of American citizens
- Dependents living outside the US
- Investors with US rental income or other taxable assets
For US expats, this usually comes up if you’re married to a non-US spouse or claiming dependents who don’t have SSNs.
2025 update: ITINs now expire after three years of non-use. If you haven’t filed for three consecutive years, you’ll need to renew through the IRS.
Need to apply for an ITIN?
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What’s the difference between an ITIN and an SSN?
An SSN serves as both a US employment ID and a tax-tracking number, while an ITIN is used only for tax purposes by individuals who aren’t eligible for an SSN.
Here’s a quick breakdown of how ITINs and SSNs differ:
|
Feature |
SSN |
ITIN |
|
Issued by |
Social Security Administration (SSA) |
Internal Revenue Service (IRS) |
|
Used for |
Work, Social Security benefits, and tax filing |
Tax filing only |
|
Eligible applicants |
US citizens & authorized workers |
Nonresidents or dependents not eligible for SSN |
|
Forms used |
Form SS-5 (SSA) |
Form W-7 (IRS) |
|
Benefit coverage |
Eligible for Social Security and Medicare |
Not eligible |
|
Expiration |
Permanent |
Expires after 3 years of non-use |
|
Use abroad |
Still valid for US taxes |
Commonly used by expats’ spouses or dependents |
Do US expats need an ITIN or an SSN?
If you’re a US citizen or a Green Card holder, you’ll always use your SSN, even while living abroad. You generally won’t need an ITIN yourself, since ITINs are meant for people who aren’t eligible for an SSN.
However, you might need to include ITINs for people connected to you, such as:
- A non-US spouse you’re filing jointly with,
- Dependents who live abroad and don’t qualify for SSNs, or
- Foreign partners or investors who share US income with you.
Important! US expats can’t have both active. Once you receive an SSN, notify the IRS; they will void your ITIN and combine your records. Don’t use both!
Can I file US taxes from abroad without an SSN?
Yes. You can file with an ITIN. The IRS accepts Form 1040 with a valid ITIN attached to Form W-7, even if you’re filing from another country.
How can I get an ITIN from outside the US?
You can apply for an ITIN from abroad by following these steps:
- Fill out Form W-7 and attach it to your US tax return.
- Include proof of your foreign status, like a passport or national ID.
- Send your application using one of these options:
- By mail to the IRS
- Through an IRS-authorized Acceptance Agent (many operate internationally)
- At a US consulate
- Renew your ITIN if you haven’t used it on a tax return in the last three years.
Tip: If you’re filing jointly with a non-US spouse, both of you need to sign the return and include identity documents.
How do I apply for an SSN while living abroad?
You can still get or replace an SSN from outside the US. Here’s how:
- Complete Form SS-5. This is the official application for a Social Security card.
- Gather your documents to prove:
- Citizenship or immigration status (such as a US passport or Green Card),
- Identity, and
- Work authorization (if you’re not a citizen).
- Send your application using one of these options:
- Nearest US Embassy, consulate
- The SSA field office that handles Social Security services for people abroad.
- Wait for processing. Processing times vary by country and method; expect several weeks.
2025 update: The SSA’s new digital verification system lets some applicants confirm identity online before submitting documents.
FAQs
-
Can I have both an SSN and ITIN?
No. Once you receive an SSN, the IRS will deactivate your ITIN.
-
Can I use my SSN while living overseas?
-
Can my non-US spouse get an SSN?
-
Is ITIN renewal automatic?
-
Can I open a US bank account abroad with an ITIN?
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What if I used an expired ITIN on my tax return?
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