Where to find your tax ID number if you already have one

Your tax ID number is printed on documents you have already received from the IRS. The fastest way to locate it is to check paperwork you have at home right now.

Look for your tax ID on any of these documents: your most recent tax return (Form 1040, 1040-SR, or 1040-NR), your Social Security card, your W-2 form from an employer, your 1099 form from a client or bank, or any notice the IRS has sent you by mail. The number appears in the same place on all of them. If you file taxes jointly with a spouse, each person has their own separate tax ID.

If you cannot find a paper copy, you can log into your IRS account online at irs.gov using your Social Security number and date of birth. Once you are logged in, your tax ID will display on your account dashboard. You do not need to create a new account if you already filed taxes — the IRS has a record of you.

Key Takeaways

  • Your tax ID is your Social Security number if you are a U.S. citizen or permanent resident filing individual taxes.
  • Check your last tax return, W-2, 1099, or any IRS letter — your tax ID appears on all of them.
  • You can view your tax ID by logging into your IRS account at irs.gov with your Social Security number and date of birth.
  • If you are self-employed or run a business, your tax ID may be an Employer Identification Number (EIN) instead, which you can look up on the IRS website using your business name and formation date.

What your tax ID actually is

For most people, your tax ID is simply your Social Security number. The IRS uses it to track your income, tax payments, and filing history. You do not need to request it or do anything to get it — if you have a Social Security number, that is your tax ID.

If you are self-employed, own a business, or hire employees, you have a different tax ID called an Employer Identification Number (EIN). An EIN is a nine-digit number that looks like this: 12-3456789. You request an EIN from the IRS when you start a business, and it becomes your tax ID for that business instead of your Social Security number.

Non-citizens who do not have a Social Security number but file U.S. taxes receive an Individual Taxpayer Identification Number (ITIN) from the IRS. An ITIN looks like a Social Security number but starts with the number 9. If you have an ITIN, that is your tax ID for filing purposes.

How to look up an EIN if you own a business

If you started a business and received an EIN, you can find it on your IRS paperwork or by searching the IRS EIN database online. Go to irs.gov and use the search bar to find "EIN lookup." You will need your business name and the date your business was formed.

The IRS database shows whether an EIN is currently active and what type of business it is registered to. If you cannot remember your EIN and do not have the paperwork, you can also call the IRS Business and Specialty Tax Line at 1-800-829-4933. Have your business name, formation date, and Social Security number ready when you call.

If you applied for an EIN but never received a confirmation letter, the IRS can tell you whether it was issued. The confirmation letter (Form SS-4) is the official record of your EIN, so keep it in a safe place once you receive it.

What to do if you cannot locate your tax ID

If you have filed taxes before but cannot find your tax ID anywhere, the IRS can look it up for you. Call the IRS at 1-800-829-1040 during business hours. You will need to provide your name, date of birth, and address. The IRS representative will confirm your tax ID over the phone.

If you have never filed taxes and do not have a Social Security number, you will need to apply for one first. Contact your local Social Security office or visit ssa.gov to start that process. Once you have a Social Security number, that becomes your tax ID automatically.

If you are not a U.S. citizen and do not have a Social Security number, you can request an ITIN by filing Form W-7 with the IRS. You will need to include documents that prove your identity and foreign status. The process takes several weeks, and the IRS will mail your ITIN to you once it is approved.

Why you might need to look up your tax ID

You need your tax ID when you file your annual tax return, when you open a bank account, when you apply for a loan or credit card, or when you start a job and fill out a W-4 form. Employers, banks, and government agencies use it to verify who you are and to track financial records in your name.

If you are helping someone else with their taxes or financial matters, they will need to provide their tax ID to you. Never share your tax ID with anyone you do not trust, because it can be used to file false tax returns or commit identity theft in your name.

Frequently Asked Questions

Is my tax ID the same as my Social Security number?

Yes, for most people. If you are a U.S. citizen or permanent resident filing individual taxes, your Social Security number is your tax ID. If you own a business, your tax ID is an EIN instead. If you are a non-citizen without a Social Security number, your tax ID is an ITIN.

Can I look up someone else's tax ID?

No. Tax ID numbers are private information protected by federal law. Only the person who owns the tax ID, their spouse (if filing jointly), or someone with legal power of attorney can look it up. Employers and financial institutions can see your tax ID because you provide it to them directly.

What if I lost my Social Security card but still need my tax ID?

Your tax ID is your Social Security number, so you do not need the card itself. You can look it up on any tax return you have filed, any W-2 or 1099 you received, or by logging into your IRS account online. If you need a replacement Social Security card, contact your local Social Security office.

How long does it take to get an EIN after I request one?

If you request an EIN online at irs.gov, you receive it immediately. If you request one by phone or mail, it takes about two weeks. Once you have an EIN, you can use it right away for business purposes.