What Your Tax ID Number Is and Where to Find It

Your tax ID number is a nine-digit identifier the IRS uses to track your tax account. For most people, this is your Social Security Number (SSN). If you are self-employed, own a business, or operate as a partnership or corporation, you have a separate Employer Identification Number (EIN) instead of or in addition to your SSN.

The number you need depends on what you are filing. If you work as an employee and file individual taxes, your SSN is your tax ID. If you run a business or hire employees, you need an EIN. Some people have both — they use their SSN for personal returns and an EIN for business returns.

Finding your tax ID takes seconds if you know where to look. Your SSN appears on your Social Security card, tax returns from previous years, W-2 forms, and bank statements. Your EIN appears on IRS correspondence, your business tax returns, and the confirmation letter you received when you first registered it.

Key Takeaways

  • Your Social Security Number is your tax ID if you file as an individual employee; an Employer Identification Number is your tax ID if you own a business or partnership.
  • Your SSN appears on your Social Security card, previous tax returns, W-2 forms, and most bank statements.
  • Your EIN appears on IRS letters, your business tax returns, and the confirmation letter sent when you first registered the number.
  • If you cannot locate your SSN or EIN, you can request it from the Social Security Administration or the IRS using specific forms.

Finding Your Social Security Number

Your Social Security Number is printed on your physical Social Security card. If you have the card, the nine-digit number is on the front. If you have lost the card, check any tax documents you filed in the past three years — your SSN appears on Form 1040 (your individual tax return), W-2 forms from employers, 1099 forms for other income, and bank statements that report interest or dividends.

You can also find your SSN on your driver's license or state ID in some states, though not all include it. Check your health insurance card — many insurers print the SSN on the card or in your account documents. If you have a mortgage, car loan, or credit card, your SSN is in the loan or account paperwork.

If none of these documents are available, contact the Social Security Administration directly. Call 1-800-772-1213 (TTY 1-800-325-0778) or visit your local Social Security office. You will need to bring a photo ID and proof of citizenship or legal residency. Processing a replacement card takes one to two weeks.

Finding Your Employer Identification Number

If you registered an EIN with the IRS, you received a confirmation letter in the mail — this letter contains your nine-digit EIN. Keep this letter in your business records. If you cannot find it, check any business tax returns you have filed (Form 1120 for corporations, Form 1065 for partnerships, Schedule C for sole proprietors). Your EIN appears at the top of these forms.

Look through IRS correspondence you have received. Any letter from the IRS about your business account will show your EIN. If you have a business bank account, the EIN may appear on statements or account documents. Some business licenses or permits issued by your state or local government also list the EIN.

If you cannot locate your EIN through these sources, you can request it from the IRS. Call the Business and Specialty Tax Line at 1-800-829-4933 (Monday through Friday, 7 a.m. to 7 p.m. your local time). Have your business name, address, and the approximate date you registered the EIN ready. The IRS can provide it over the phone when ready.

What to Do If You Cannot Find Your Number

If you have lost or cannot locate your SSN, the Social Security Administration can issue a replacement card. Visit ssa.gov to find your nearest Social Security office, or call 1-800-772-1213. You will need to provide a photo ID (driver's license, passport, or state ID) and proof that you are a U.S. citizen or lawful resident (birth certificate, naturalization papers, or immigration documents). There is no fee for a replacement card.

If you cannot find your EIN, the IRS can look it up for you by phone. Call 1-800-829-4933 and have your business name, address, and the year you registered ready. If you registered the EIN online, you may also be able to retrieve it through your IRS online account at irs.gov if you have set up login credentials.

If you registered an EIN but never received the confirmation letter and cannot reach the IRS by phone, you can submit Form SS-4 again. The IRS will send you a new confirmation letter with your EIN. You can file Form SS-4 online at irs.gov, by fax, or by mail — the online method is fastest and provides your EIN when ready on screen.

When You Need Your Tax ID for Different Situations

You will need your SSN when you file your individual tax return, open a bank account, explore for credit, get a job, or claim dependents. Employers ask for your SSN on the W-4 form before your first paycheck. Banks and credit card companies ask for it when you open an account. The IRS requires it on every tax return you file.

You will need your EIN when you file a business tax return, open a business bank account, hire employees, explore for a business loan, or register for state and local business licenses. If you have employees, you must provide your EIN to them so they can report your business on their own tax returns. Vendors and contractors may also ask for your EIN before doing business with you.

Some situations require both numbers. If you are a sole proprietor (self-employed with no employees), you typically use your SSN as your business tax ID and do not need a separate EIN — though you can obtain one if you prefer. If you have employees or operate as a partnership or corporation, you must have an EIN separate from your personal SSN.

Protecting Your Tax ID Number

Your tax ID number is sensitive information. Treat it the same way you treat a password — do not share it unless you are certain the person or organization asking for it has a legitimate reason. Employers, banks, the IRS, and government agencies will ask for it. Scammers also ask for it, so verify you are dealing with a real organization before you provide it.

Do not carry your Social Security card in your wallet. Store it in a safe place at home. When you receive documents with your SSN or EIN, shred them before throwing them away. If you suspect someone has stolen your tax ID or used it fraudulently, contact the IRS when ready at 1-800-829-1040 and file a report with the Federal Trade Commission at reportidentitytheft.ftc.gov.

Frequently Asked Questions

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

For most people, yes. Your Social Security Number is your tax ID if you file individual taxes as an employee. If you own a business, you have a separate Employer Identification Number that serves as your business tax ID, though you still use your SSN for personal tax matters.

Can I change my tax ID number?

You cannot change your Social Security Number straightforward because you want a new one. The Social Security Administration only issues a new SSN in cases of identity theft or documented harassment. You can obtain a new EIN if your business structure changes or if you have documented evidence of identity theft affecting your business account.

What if I have never had a Social Security Number?

Contact the Social Security Administration at 1-800-772-1213 or visit your local office. You will need to provide proof of identity, age, and citizenship or lawful residency. The SSA will issue you a number and card. Processing takes one to two weeks.

Do I need an EIN if I am self-employed with no employees?

No. As a sole proprietor with no employees, you can use your Social Security Number as your business tax ID. You only need an EIN if you have employees, operate as a partnership or corporation, or prefer to keep your business and personal finances separate for privacy.

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

Your tax ID appears at the top of your tax return form. On Form 1040 (individual return), it is labeled "Your social security number." On business forms like Form 1120 or 1065, it is labeled "Employer identification number" and appears near the top of the first page.