Your Tax ID Number Is on Documents You Already Have

Your tax ID number appears on multiple documents you receive from the IRS or your employer — you do not need to request it separately. For most people, it is your Social Security number. If you are self-employed or run a business, you have an Employer Identification Number (EIN) instead, which the IRS issued when you registered your business.

The fastest way to find your number is to check the documents listed in the sections below. If you cannot locate it that way, you can contact the IRS directly or retrieve it from your online account. The method you choose depends on which type of number you need and how quickly you need it.

Key Takeaways

  • Your Social Security number is your tax ID if you work as an employee; it appears on your W-2 form, pay stub, and tax return.
  • An Employer Identification Number (EIN) is your tax ID if you own a business; the IRS sent it to you by mail when you registered.
  • You can find your EIN on IRS correspondence, your business tax return, or by logging into your IRS online account.
  • The IRS can confirm your tax ID by phone or mail if you cannot locate it in your documents.

Finding Your Social Security Number

If you are an employee, your tax ID is your Social Security number. Check your most recent W-2 form — the box labeled "a" at the top left shows your Social Security number. You can also find it on your current pay stub, usually in the earnings section or at the top of the document.

Your Social Security number also appears on your federal tax return (Form 1040) if you filed one. If you filed taxes last year, look at the copy you kept or the confirmation the IRS sent you. Your Social Security card itself has the number printed on it, though you may not need to carry the physical card to provide the number.

Finding Your Employer Identification Number (EIN)

If you own a business, your tax ID is your Employer Identification Number. The IRS mailed this nine-digit number to you when you first registered your business. Check the original letter from the IRS — it typically arrived within two weeks of your registration and is labeled "EIN Assignment Notice" or "Notice of Employer Identification Number Assignment."

Your EIN also appears on your business tax return (Form 1120, 1120-S, or 1065, depending on your business structure). If you filed a business return, look at the copy you kept or the IRS confirmation. You can also find it on any IRS correspondence about your business, such as notices about estimated tax payments or payroll tax filings.

Checking Your IRS Online Account

You can view your tax ID number by logging into your account on IRS.gov. Create a login using your Social Security number or EIN, then answer security questions to verify your identity. Once logged in, your account dashboard displays your tax ID number at the top.

This method works for both individual and business accounts. You will need a valid email address and a phone number on file with the IRS. If you do not have an online account yet, you can create one in about 10 minutes. The IRS also offers a mobile app called "IRS2Go" where you can view your account information after logging in.

Contacting the IRS by Phone or Mail

If you cannot find your tax ID number in your documents or online account, you can call the IRS directly. For individuals, call the IRS at 1-800-829-1040 (Monday through Friday, 7 a.m. to 7 p.m. your local time). For businesses, call 1-800-829-4933. Have your name, address, and date of birth ready when you call.

You can also request your tax ID number by mail. Send a letter to the IRS office that serves your area, include your name and address, and ask them to confirm your tax ID number. The IRS will respond by mail within 30 days. This method takes longer but creates a paper record of your request.

What to Do If You Never Received Your EIN

If you registered a business but never received an EIN assignment notice, check your mail carefully — the letter may have arrived months ago. Look through old mail or ask anyone else who may have received it on behalf of your business.

If the letter is truly lost, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933 and provide your business name and registration date. They can confirm whether an EIN was issued and tell you the number. You can also check the IRS website by entering your business information into their EIN lookup tool if your business is registered with your state.

Frequently Asked Questions

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

Yes, if you are an employee or self-employed individual without a business. Your Social Security number is your tax ID for filing personal tax returns. If you own a business, you have a separate Employer Identification Number instead.

Can I find my EIN if I lost the IRS letter?

Yes. Call the IRS at 1-800-829-4933 with your business name and the date you registered. They will confirm your EIN over the phone. You can also check your business tax return or any IRS notices sent to your business address.

What if I do not have a W-2 or pay stub?

Log into your IRS account online at IRS.gov, or call 1-800-829-1040 with your name, address, and date of birth. The IRS can confirm your Social Security number without needing documents in hand.

How long does it take to get a new EIN if mine is lost?

You do not need a new EIN. The number you were issued is permanent and does not change. The IRS can confirm it by phone or mail if you cannot locate your original assignment notice.

Can I use my tax ID number online safely?

Your tax ID number is necessary for many financial and tax purposes, so you will need to share it in find settings. Only enter it on official IRS websites or with trusted financial institutions. Never share it in response to unsolicited emails or calls claiming to be from the IRS.