Your Tax ID is on documents you already have

Your Tax ID number — also called an EIN (Employer Identification Number) if you're self-employed or own a business, or your SSN (Social Security Number) if you're an individual — appears on multiple documents you've received from the government or your employer. You don't need to request it; you need to locate it.

If you're an individual filing taxes, your Tax ID is your Social Security Number. If you own a business or are self-employed, you have an EIN instead. The document that holds this number depends on which one you have and when you received it.

Key Takeaways

  • Your Social Security Number is your Tax ID if you file as an individual; your EIN is your Tax ID if you own a business or are self-employed.
  • Your Social Security Number appears on your Social Security card, tax returns, W-2 forms, and bank statements.
  • Your EIN appears on IRS correspondence, business tax returns, and the SS-4 form you received when you first registered the business.
  • If you cannot locate your number in these documents, the IRS can look it up for you by phone or mail using your name and date of birth.

Where to find your Social Security Number

Your Social Security Number is printed on your Social Security card, which you received from the Social Security Administration. If you still have it, the nine-digit number is on the front. If you've lost the card, the number also appears on:

  • Any tax return you've filed (Form 1040, 1040-SR, or 1040-NR)
  • Your W-2 form from an employer
  • Your 1099 form if you received self-employment or contract income
  • Bank statements or investment account statements
  • Your driver's license or state ID (some states print it, others do not)

If you filed taxes last year, your tax return is the fastest place to look. The IRS mails copies of accepted returns, and you can also view your return through your tax software account or by logging into IRS.gov with your username and password.

Where to find your Employer Identification Number

If you own a business or are self-employed, your EIN is a nine-digit number assigned by the IRS. It appears on the SS-4 form (Application for an Employer Identification Number) that you filed when you first registered your business. The IRS sent you a confirmation letter with the EIN on it.

Your EIN also appears on:

  • Any business tax return you've filed (Form 1120, 1120-S, 1065, or 1040-C)
  • IRS correspondence or notices addressed to your business
  • Your business bank account statements
  • Payroll records if you have employees
  • 1099 forms you've issued to contractors

The SS-4 confirmation letter is the official record. If you filed for an EIN years ago and cannot find the letter, check your business files, email archives, or the folder where you keep tax documents.

How to look up your number through the IRS

If you've searched your documents and cannot find your number, the IRS can look it up for you. You'll need to call the IRS directly or submit a written request.

To call the IRS, use the phone number on your most recent tax notice or visit IRS.gov and search for "IRS phone numbers." Have your name, date of birth, and mailing address ready. Wait times are often long, especially during tax season (January through April).

To request your number by mail, send a letter to the IRS office that serves your area. Include your name, date of birth, mailing address, and a brief explanation of what you're looking for. The IRS will respond by mail within two to four weeks. You can find the correct mailing address on IRS.gov under "Where to File."

What to do if you've never had a Tax ID

If you're an individual who has never worked or filed taxes, you don't have a Social Security Number yet. You can request one from the Social Security Administration by visiting your local Social Security office or applying online at ssa.gov. You'll need to provide proof of identity, age, and citizenship or immigration status.

If you own a business but never filed for an EIN, you can request one now through the IRS. You can apply online at IRS.gov (instant confirmation), by phone at 1-800-829-4933, by fax, or by mail using Form SS-4. Online applications are processed immediately and give you your number right away.

Frequently Asked Questions

Is my Social Security Number the same as my Tax ID?

Yes, if you're an individual filing taxes. Your Social Security Number is your Tax ID. If you own a business or are self-employed, your Tax ID is your EIN instead, which is a separate nine-digit number.

Can I look up someone else's Tax ID number?

No. Tax ID numbers are confidential. The IRS will only provide a number to the person it belongs to or an authorized representative with power of attorney. You cannot look up another person's number online or by phone.

What if I lost my Social Security card?

You don't need the card to find your number — it's on your tax returns, W-2 forms, and bank statements. If you need a replacement card, visit your local Social Security office or apply online at ssa.gov. Replacement cards take one to two weeks.

Do I need my Tax ID to file taxes?

Yes. The IRS requires your Tax ID on every tax return. If you don't have one, you must request it before filing. For individuals, that means getting a Social Security Number; for businesses, that means getting an EIN.