Your tax ID is a nine-digit number the IRS uses to identify you for tax filing and reporting

A tax ID is how the Internal Revenue Service tracks your tax account. If you are a U.S. citizen or resident alien, this is your Social Security Number (SSN). If you do not have an SSN but need to file taxes or open a business, you will have an Employer Identification Number (EIN) instead. Both are nine digits, formatted differently, and serve the same purpose: linking you to your tax records.

The number you need depends on why you are looking for it. Most individual filers already know their SSN. Business owners, nonprofits, and people filing taxes without an SSN need an EIN. This guide covers how to find whichever one applies to you, and what to do if you have lost track of it.

Key Takeaways

  • Your Social Security Number is your tax ID if you are an individual filer; your Employer Identification Number is your tax ID if you own a business or operate as a partnership or corporation.
  • You can find your SSN on your Social Security card, tax returns, W-2 forms, or bank statements; you can find your EIN on IRS correspondence or by searching the IRS Business Name Search tool online.
  • If you have lost your SSN, you must visit a Social Security Administration office in person with a birth certificate and photo ID to request a replacement card.
  • If you have lost your EIN, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933 with your business information to retrieve it.
  • You do not need to request a new tax ID if you already have one; the IRS will not issue a second SSN or EIN to the same person or business.

Finding Your Social Security Number

Your Social Security Number is printed on your Social Security card, which you received when you first applied for one. If you still have the card, the nine-digit number is on the front. If you have lost the card but need the number, check any of these documents: your most recent tax return (Form 1040 or 1040-SR), a W-2 form from an employer, a 1099 form from a contractor or bank, your driver's license or state ID, or bank and investment statements.

Tax returns and W-2 forms are the most reliable sources because they are official IRS documents. If you filed taxes last year, you can retrieve a copy of your return from the IRS by calling 1-800-829-1040 or by creating an account on IRS.gov and using the "Get Transcript" tool. The transcript will show your SSN.

If you cannot find your number in any of these places, you will need to contact the Social Security Administration directly. Call 1-800-772-1213 (TTY 1-800-325-0778) to request a replacement Social Security card. You will need to visit a Social Security office in person with your original birth certificate and a photo ID such as a driver's license or passport. The office will issue you a new card with the same number you have always had.

Finding Your Employer Identification Number

An Employer Identification Number (EIN) is a nine-digit number assigned to businesses, nonprofits, trusts, and certain other entities. If you own a business or run a nonprofit, this is your tax ID instead of an SSN. The IRS issued your EIN when you first requested one, usually through Form SS-4.

Your EIN appears on any official IRS correspondence sent to your business, including notices, letters about tax payments, or confirmation of your EIN assignment. Check your files for these documents first. If you have them, the EIN is printed clearly on the letter or notice.

If you cannot find the original paperwork, you can search for your EIN using the IRS Business Name Search tool at the IRS website. Enter your business name and the state where it is registered; the tool will return your EIN if it is on file. This search is free and does not require you to log in.

If the search tool does not find your number, call the IRS Business and Specialty Tax Line at 1-800-829-4933. Have your business name, address, and the approximate year you received the EIN ready. The IRS representative can look up your number in their system and provide it over the phone.

What to Do If You Have Never Had a Tax ID

If you have never had an SSN and need one to file taxes or work in the United States, you must explore through the Social Security Administration. Visit your local Social Security office with your birth certificate, passport or travel document, and a completed Form SS-5 (process for a Social Security Card). The office will issue you a card and number on the spot or within two weeks.

If you need an EIN for a new business, you can request one when ready through the IRS. The fastest way is to explore online at IRS.gov using Form SS-4. The online process takes about 15 minutes and you receive your EIN the same day. You can also mail Form SS-4 to the IRS (processing takes about four weeks) or call 1-800-829-4933 to explore by phone.

Understanding the Difference Between SSN and EIN

A Social Security Number is issued to individuals and is tied to your personal identity. It is used for employment, tax filing, credit, and Social Security benefits. You receive one SSN in your lifetime and keep it even if you change jobs, move, or change your name.

An Employer Identification Number is issued to businesses, nonprofits, partnerships, and corporations. It is not tied to a person; it is tied to the business entity itself. If you close a business and start a new one, you will receive a new EIN. If you are a sole proprietor (self-employed with no employees), you can use your SSN as your tax ID, but many sole proprietors request an EIN to keep their personal and business finances separate.

Some people and businesses have both numbers. For example, a business owner has an SSN for personal tax filing and an EIN for the business. When you file taxes, you use the number that matches the type of return you are filing: your SSN for Form 1040 (individual return) and your EIN for Form 1120 (corporate return) or Form 1065 (partnership return).

Replacing a Lost or Stolen Tax ID

If your Social Security card is lost or stolen, contact the Social Security Administration at 1-800-772-1213 to request a replacement. You will need to visit an office in person with your birth certificate and photo ID. There is no fee for a replacement card, and you will receive a new card with the same nine-digit number. The number itself does not change; only the physical card is replaced.

If you suspect your SSN has been used fraudulently, place a fraud alert with the three major credit bureaus (Equifax, Experian, and TransUnion) by calling 1-800-525-6285. You can also file a report with the Federal Trade Commission at IdentityTheft.gov. These steps do not change your SSN but alert creditors to verify your identity before opening new accounts.

If your EIN has been compromised or you believe it has been used fraudulently, contact the IRS at 1-800-829-4933. The IRS will not issue you a new EIN; instead, they will review your account for suspicious activity and help you find it. Keep records of any fraudulent use to report to the IRS and to your accountant or tax preparer.

Frequently Asked Questions

Where do I find my tax ID on my tax return?

Your Social Security Number appears in the top right corner of Form 1040 (individual return). Your Employer Identification Number appears in the same location on Form 1120 (corporate return) or Form 1065 (partnership return). If you filed electronically, you can view your return by logging into your IRS account at IRS.gov or by requesting a transcript.

Can I get a new tax ID if I want a different number?

No. The IRS does not issue a second Social Security Number or Employer Identification Number to the same person or business. Your tax ID is permanent and tied to your identity or business entity. If you want to separate personal and business finances, you can request an EIN as a sole proprietor, but you cannot replace your existing SSN or EIN.

Do I need a tax ID to file taxes if I am self-employed?

Yes. You must use either your Social Security Number or an Employer Identification Number on your tax return. Most self-employed people use their SSN. If you want to keep your business finances separate from your personal finances, you can request an EIN for free through the IRS, even if you have no employees.

What if I do not remember my tax ID and cannot find any documents with it?

Call the IRS at 1-800-829-1040 and provide your name, address, and date of birth. The IRS can look up your Social Security Number in their system. If you need your Employer Identification Number, call the Business and Specialty Tax Line at 1-800-829-4933 with your business name and address. Both services are free.

Is my tax ID the same as my account number on my tax return?

Your tax ID (SSN or EIN) is your account number with the IRS. They are the same nine-digit number. The IRS uses this number to match you to your tax records, payments, and any correspondence about your account.