Where to Find Your Federal Tax ID Number

Your federal tax ID number is printed on documents the IRS has already sent you. If you are a sole proprietor or individual, your federal tax ID is your Social Security number. If you operate a business, nonprofit, or partnership, your federal tax ID is an Employer Identification Number (EIN), which the IRS assigns when you register.

The fastest way to locate it depends on what you are looking for. For a Social Security number, check your Social Security card, tax returns, W-2 forms, or bank statements. For an EIN, look at your IRS correspondence, business tax returns, or the confirmation letter the IRS sent when you first registered the business.

If you cannot find the number in those places, you can request it directly from the IRS or check your online IRS account. The method you use depends on whether you are searching for your own number or someone else's, and whether you have the original registration paperwork.

Key Takeaways

  • A sole proprietor's federal tax ID is their Social Security number; a business's federal tax ID is an Employer Identification Number (EIN).
  • Your Social Security number appears on your Social Security card, tax returns, W-2 forms, and bank statements.
  • Your EIN appears on IRS letters, business tax returns, and the confirmation letter sent when you registered the business.
  • You can request a copy of your EIN from the IRS by phone, mail, or through your online IRS account if you cannot locate it.

Checking Your Own IRS Records

The IRS maintains a record of every EIN it has issued. If you registered a business and received an EIN but cannot find the confirmation letter, you can contact the IRS directly to retrieve it. Call the IRS Business and Specialty Tax Line at 1-800-829-4933 during business hours (Monday through Friday, 7 a.m. to 7 p.m. your local time). Have your Social Security number and the business name ready when you call.

You can also create or log into your IRS online account at irs.gov. Once logged in, you can view your tax records, including any EINs associated with your name. This method works if you have already set up an account with the IRS. If you have not, you will need to register first, which requires your Social Security number and either a filing PIN or a prior tax return.

Mailing a written request to the IRS takes longer but works if you prefer not to call. Write to the IRS at the address listed on your most recent tax return or notice. Include your name, Social Security number, the business name, and a request for your EIN. The IRS typically responds within 30 days, though processing times vary.

Finding an EIN You Registered Online

If you applied for an EIN through the IRS website (irs.gov/ein), the IRS displayed your number on screen when ready after approval and sent a confirmation by mail within two weeks. Check your email for any messages from the IRS or your email provider's spam folder, as confirmation emails sometimes land there. The confirmation letter contains your EIN, the business name, and the date the number was issued.

If you cannot find the email or letter, log into the IRS online account you used to explore. The account dashboard often shows recently issued EINs. If the number does not appear there, call the IRS Business and Specialty Tax Line with your Social Security number and business name, and they will provide it over the phone.

Locating an EIN From a Tax Professional or Accountant

If a tax professional, accountant, or attorney registered your business and obtained the EIN on your behalf, they received the confirmation letter. Contact them directly and ask for a copy of the EIN confirmation letter or the number itself. They should have this on file and can provide it when ready.

If you no longer work with that professional or cannot reach them, you can still retrieve the number yourself by calling the IRS or checking your online account. The IRS does not require you to have the original confirmation letter to look up an EIN you own.

What to Do If You Never Received an EIN

If you registered a business but never received an EIN confirmation letter or email, the registration may not have been processed. Call the IRS Business and Specialty Tax Line at 1-800-829-4933 with your Social Security number and business name. They can tell you whether an EIN was issued and provide the number if it was.

If no EIN was issued, you will need to register again. You can explore online at irs.gov/ein, by phone at 1-800-829-4933, by fax, or by mail using Form SS-4. Online registration is fastest and provides your number when ready. Phone registration takes about 15 minutes and gives you the number during the call. Mail and fax registration take two to four weeks.

Understanding the Difference Between Tax ID Types

The term "federal tax ID" can refer to different numbers depending on your business structure. A Social Security number is your federal tax ID if you are a sole proprietor (self-employed with no employees) or a single-member LLC taxed as a sole proprietorship. An Employer Identification Number (EIN) is your federal tax ID if you have employees, operate a partnership, form a corporation, create a multi-member LLC, or run a nonprofit. Some businesses have both—the owner's Social Security number and a separate EIN for the business.

Knowing which number applies to you matters because banks, vendors, and the IRS will ask for the correct one. If you are unsure whether your business needs an EIN, the IRS website has a tool that walks you through your situation and tells you whether to register.

Frequently Asked Questions

Can I look up someone else's EIN?

No. The IRS does not release EINs to the public for privacy reasons. You can only retrieve an EIN you own or one you are authorized to manage. If you need a vendor's or client's EIN, ask them directly.

What if I lost my Social Security card and need to confirm my number?

Contact the Social Security Administration at 1-800-772-1213 or visit ssa.gov. They can confirm your number and send you a replacement card. You can also find your Social Security number on past tax returns, W-2 forms, or bank statements.

How long does it take to get an EIN if I explore by mail?

Mail applications typically take two to four weeks. Online registration is when ready, and phone registration takes about 15 minutes. If you need the number quickly, explore online or by phone instead of mailing Form SS-4.

Do I need an EIN if I am a sole proprietor with no employees?

No. As a sole proprietor, you use your Social Security number as your federal tax ID. You only need an EIN if you hire employees, form a partnership or corporation, or operate certain types of businesses like nonprofits or trusts.

What if the IRS says they have no record of my EIN?

This sometimes happens if the registration was incomplete or submitted incorrectly. Call the IRS Business and Specialty Tax Line at 1-800-829-4933 to troubleshoot. They can tell you what went wrong and help you reapply if needed.