Your Tax ID is on documents you already have

Your tax identification number is printed on your Social Security card, your most recent tax return, and any W-2 or 1099 form your employer sent you. If you are self-employed or run a business, you may have an Employer Identification Number (EIN) instead of or in addition to your Social Security number. The fastest way to locate it is to check the documents you received in the mail from the IRS or your employer — you do not need to request anything new.

If you cannot find your number on paper, the IRS website has a tool that lets you look it up using your name and date of birth. You will need to create a login on IRS.gov first. This process takes about 10 minutes and does not require you to call anyone.

Key Takeaways

  • Your Social Security number is your tax identification number unless you are self-employed or own a business, in which case you may have an EIN.
  • Check your Social Security card, last tax return, W-2, or 1099 form — your tax ID is printed on all of these.
  • The IRS online lookup tool at IRS.gov lets you find your number by logging in with your name and date of birth.
  • If you were issued an EIN for a business, that number appears on IRS correspondence and on your business tax returns.
  • You do not pay a fee to look up or replace your tax identification number.

Where to find your Social Security number

Your Social Security number is your tax identification number if you work as an employee or file taxes as an individual. It appears on the front of your Social Security card in the format XXX-XX-XXXX. If you have lost your card, the number is also on any tax return you filed, any W-2 your employer sent you, and any 1099 form you received from a bank, investment company, or other payer.

If you do not have any of these documents, you can request a replacement Social Security card from the Social Security Administration. You will need to visit a local Social Security office in person or mail in an application with a copy of your birth certificate and photo ID. The process takes about two weeks by mail or a few days if you apply in person. There is no charge for a replacement card.

How to find an Employer Identification Number (EIN)

An EIN is a nine-digit number the IRS issues to businesses, partnerships, and self-employed people who hire employees. It looks like XX-XXXXXXX. If you own a business or are self-employed, you may have an EIN in addition to your Social Security number.

Your EIN appears on any IRS letter or notice sent to your business, on your business tax return (Form 1120, 1120-S, or 1065), and on any business bank account paperwork. If you cannot locate it, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933 and provide your name, business name, and date of birth. The IRS can tell you your EIN over the phone. You can also look it up on IRS.gov if you have created a login.

Using the IRS online lookup tool

The IRS website has a tool that shows you your tax identification number without calling or visiting an office. Go to IRS.gov and create a login using your email address, Social Security number, and date of birth. Once you are logged in, you can view your tax account, which displays your identification number and recent tax history.

This tool works for both Social Security numbers and EINs. The login process takes about 10 minutes the first time. You will need a valid email address and access to a phone or email to verify your identity. After you log in once, you can return to your account anytime to check your number or other tax information.

What to do if you cannot locate your number

If you have checked all your documents and cannot find your tax identification number, contact the IRS directly. For a Social Security number, call the Social Security Administration at 1-800-772-1213. For an EIN, call the IRS Business and Specialty Tax Line at 1-800-829-4933. Both lines are open Monday through Friday, 7 a.m. to 7 p.m. your local time.

When you call, have your name, date of birth, and address ready. If you are calling about a business EIN, also have your business name and the date you started the business. The representative can tell you your number over the phone and may mail you a confirmation letter. There is no charge for this service.

Tax ID numbers for non-citizens and immigrants

If you do not have a Social Security number but need to file taxes or open a bank account, you can obtain an Individual Taxpayer Identification Number (ITIN). An ITIN is a nine-digit number in the format XX-XX-XXXX that the IRS issues to people who are not may be able to access for a Social Security number but have a tax filing requirement.

To get an ITIN, you must file Form W-7 with the IRS and include proof of identity and proof of residency. You can mail the form and documents to the IRS, or in some cases, you can apply in person at an IRS office or through a Certified Acceptance Agent. The process takes about four to six weeks by mail. There is no fee to apply for an ITIN.

Frequently Asked Questions

Where is my tax ID number on my W-2?

Your Social Security number appears in the top right corner of your W-2 form, labeled as "Employee's SSN." Your employer's EIN is also on the form, labeled as "Employer's EIN," but that is not your tax ID — it is your employer's business number.

Can I look up someone else's tax identification number?

No. The IRS online lookup tool requires you to verify your own identity using your Social Security number and date of birth. You cannot look up another person's tax ID number through any IRS tool or by calling the IRS. Only the person themselves or an authorized representative with power of attorney can access that information.

What if my tax ID number was stolen or compromised?

Contact the Social Security Administration at 1-800-772-1213 to report identity theft involving your Social Security number. You can also file a report with the Federal Trade Commission at IdentityTheft.gov. If your EIN was compromised, call the IRS at 1-800-829-4933. Both agencies can help you monitor for fraudulent use and take steps to protect your number.

Do I need my tax ID number to file taxes?

Yes. You must provide your tax identification number on any tax return you file with the IRS. If you do not have a Social Security number or EIN, you will need to obtain an ITIN before you can file. You cannot file a tax return without one of these three numbers.