Where to Find Your Federal Tax ID Number

Your Federal Tax ID is on documents you already have

Your Federal Tax ID Number — also called an EIN (Employer Identification Number) or SSN (Social Security Number) — appears on tax forms, W-2s, bank statements, and loan documents you've received. You don't need to request it; the IRS assigned it to you when you filed your first tax return or opened a business. The fastest way to find it is to look at paperwork you already have rather than contact the IRS.

If you're an individual filing personal taxes, your Federal Tax ID is your Social Security Number. If you own a business or operate as a sole proprietor, you may have both an SSN and a separate EIN. This guide covers where to locate both and what to do if you can't find yours.

Key Takeaways

Your Social Security Number is your Federal Tax ID for personal tax returns and appears on your Social Security card, tax returns, W-2s, and bank statements.
Business owners have a separate EIN, which the IRS issued when you registered your business and appears on business tax returns and bank account paperwork.
The IRS website has a lookup tool where you can search for an EIN you've already been assigned, but you cannot request a new one online.
If you've lost both your SSN and all documents showing it, you'll need to contact the Social Security Administration in person with a photo ID and birth certificate.

Where to find your Social Security Number

Your Social Security Number is printed on your Social Security card, which the Social Security Administration mailed to you. If you still have the card, the nine-digit number is on the front. If you've lost the card, check any of these documents:

Federal tax returns you've filed (Form 1040 or similar)
W-2 forms from employers
1099 forms from contractors or financial institutions
Bank statements and savings account paperwork
Mortgage or loan documents
Insurance policies (health, auto, or home)
Your driver's license or state ID (some states print it; others don't)

If you filed taxes in previous years, the IRS has your SSN on record. You can create an account on IRS.gov and view your tax transcript, which displays your Social Security Number. To do this, go to IRS.gov, select "View your tax account," and follow the identity verification steps. This usually takes a few minutes and requires you to answer security questions based on your credit history.

Where to find your Employer Identification Number (EIN)

If you own a business, you have an EIN separate from your Social Security Number. The IRS assigned this nine-digit number when you registered your business or filed your first business tax return. Your EIN appears on:

Business tax returns (Form 1120, 1120-S, or 1065)
Business bank account statements and paperwork
Business loan documents
Payroll tax forms (Form 941 or 944)
The IRS letter confirming your EIN assignment (usually sent within two weeks of application)

The IRS maintains a searchable EIN database on IRS.gov. Go to the "EIN Assistant" tool, enter your business name and address, and the system will display the EIN if it's on file. You cannot request a new EIN through this tool — it only retrieves EINs already assigned to you.

If you applied for an EIN online through IRS.gov and received a confirmation number, you can also retrieve your EIN by entering that confirmation number on the same page. The confirmation email is usually sent immediately after you complete the online application.

What to do if you cannot find your number

If you've checked all documents and cannot locate your Social Security Number, contact the Social Security Administration. You must visit a Social Security office in person — they do not issue replacements by phone or mail. Bring a photo ID (driver's license, passport, or state ID) and your birth certificate or a certified copy. The office will issue you a replacement Social Security card with your existing number on it, at no cost. Processing usually takes one to two weeks.

To find the nearest Social Security office, go to ssa.gov and use the office locator, or call 1-800-772-1213. Have your name, date of birth, and place of birth ready when you call.

If you cannot locate a business EIN and have no record of applying for one, you may not have been assigned one yet. This happens if you registered as a sole proprietor and have never hired employees or filed a business tax return. In that case, you would use your Social Security Number as your business tax ID. If you later need an EIN (for example, to hire employees), you can apply through IRS.gov or by mail using Form SS-4.

How the IRS uses your Federal Tax ID

The IRS uses your Federal Tax ID to match income reports to your tax return. Employers send W-2 forms with your SSN to the IRS; banks and investment firms send 1099 forms; and the IRS compares these to what you report on your return. If the numbers don't match, the IRS sends a notice asking for clarification.

Banks and financial institutions also use your Federal Tax ID to report interest income and to verify your identity when you open accounts. Employers use it to withhold taxes from your paycheck and to file payroll reports. If you provide an incorrect number to an employer or bank, they may not be able to process your paperwork, and the IRS may not receive the income report.

Frequently Asked Questions

Can I look up someone else's Federal Tax ID?

No. The IRS does not release Federal Tax IDs for other people. If you need to verify someone's EIN for business purposes, ask them directly or request it in writing. Some businesses publish their EIN on invoices or contracts.

What's the difference between my Social Security Number and my EIN?

Your Social Security Number is assigned to you as an individual and is used for personal tax returns, employment, and benefits. Your EIN is assigned to your business and is used for business tax returns, payroll, and business bank accounts. A sole proprietor uses their SSN unless they hire employees or choose to register for an EIN.

Do I need to memorize my Federal Tax ID?

You should know it, but you don't need to memorize it. Write it down and store it somewhere safe, like a filing cabinet or password manager. You'll need it when filing taxes, opening bank accounts, or applying for loans.

What if I've never filed taxes — do I have a Federal Tax ID?

If you're a U.S. citizen or permanent resident, you have a Social Security Number assigned at birth or when you received your green card. If you've never filed taxes, your SSN is still your Federal Tax ID; you just haven't used it for tax purposes yet. If you own a business but have never filed a business return, you may not have an EIN until you apply for one.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.