ITIN, SSN or EIN: which one do you need?
There are three federal numbers, and they aren't interchangeable. Which one fits depends on whether you can work in the US, whether you have a tax filing need, and whether you have a business.
Reviewed by Alex Thomas · Updated Nov 5, 2026
Based on your answers, you need ITIN + EIN.
Your numbers
ITIN
Individual Taxpayer Identification Number. For people who must file or appear on a return but can't get an SSN.
Apply with Form W-7, usually attached to the tax return that needs it.
EIN
Employer Identification Number. Identifies a business, not a person.
Apply free with the IRS. Without an SSN or ITIN, use Form SS-4 by fax or mail instead of the online form.
You can't keep both an SSN and an ITIN. Once you get an SSN, stop using the ITIN and ask the IRS to combine your tax records.
Ask members who've been there
Questions
Can I use an ITIN instead of an SSN?
Can I get an EIN without an SSN?
What happens to my ITIN when I get an SSN?
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Read guide →- Where can I get my Tax ID?Your Tax ID comes from the agency that issues it. Ask Social Security for an SSN if you're a citizen or allowed to work in the US. File IRS Form W-7 for an ITIN if you can't get an SSN but have a tax reason. A business gets an EIN from the IRS. SSNs and EINs are free.
- What do I do with my ITIN after I get an SSN?After you get an SSN, stop using your ITIN and use the SSN on every tax return. Then tell the IRS, by letter or at a local IRS office, so it combines your tax records under the SSN and voids the ITIN. Without that step, you may not get credit for all wages and withholding.
- Where can I find my TIN number?Your TIN is printed on the paperwork that came with it. An SSN is on your Social Security card and W-2. An ITIN is on the IRS CP565 letter that assigned it. An EIN is on the IRS notice from when you applied. Past tax returns show it too. If you can't find it, call the agency that issued it.
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Join ITIN Club — it's free
Ask members who've already done it, follow the first-year course step by step, and message other members directly. No SSN needed.