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 Employer Identification Number (EIN) if you own a business, or your Social Security Number (SSN) if you file as an individual — appears on tax forms you have already received or filed. The IRS does not mail it to you separately. You find it by looking at past tax paperwork, contacting the IRS directly, or checking your business registration records.

If you have filed a federal tax return in the past five years, your SSN or EIN is on that return. If you have never filed and need an EIN for a new business, you can request one from the IRS when ready — it takes minutes online or a few days by mail.

Key Takeaways

Your Social Security Number serves as your federal tax ID if you file taxes as an individual; it appears on any tax return you have filed.
An Employer Identification Number (EIN) is your federal tax ID if you own a business; you can find it on business tax returns, bank statements, or loan documents.
The IRS can look up your SSN or EIN by phone at 1-800-829-1040 if you provide your name, address, and date of birth.
You can request a new EIN online through the IRS website at irs.gov, which generates your number when ready, or by mail using Form SS-4.

Finding your Social Security Number on past tax documents

If you filed a federal income tax return in the past five years, your SSN is printed on that return. Check your files for Form 1040, 1040-SR, 1040-NR, or any other income tax form you submitted. The SSN appears in the top-right corner of the first page.

You can also find your SSN on a W-2 form your employer sent you, a 1099 form from a bank or contractor, or a tax transcript from the IRS. If you filed jointly with a spouse, your SSN is listed separately from theirs on the return.

If you cannot locate a paper copy, you can order a tax transcript from the IRS. Call 1-800-829-1040 and request a "Return Transcript" or "Account Transcript" for the year you need. The IRS will mail it to you, and it will show your SSN.

Finding your Employer Identification Number if you own a business

If you own a business and have an EIN, it appears on your business tax returns (Form 1120, 1120-S, 1065, or 1040-C), your business bank statements, and any business loan documents. Check the files you received when you opened your business bank account or applied for a loan.

Your EIN also appears on W-2 forms you issued to employees and on 1099 forms you sent to contractors. If you filed a business tax return, the EIN is in the top-right corner, just as your SSN would be on a personal return.

If you have been in business for several years but cannot find your EIN, the IRS can look it up by phone. Call 1-800-829-1040 and provide your business name, address, and the name of the person who applied for it. The IRS representative will read it to you over the phone.

Requesting a new EIN from the IRS if you do not have one

If you own a business and have never received an EIN, you can request one from the IRS. The fastest method is online through the IRS website at irs.gov. Search for "explore for an EIN" and follow the prompts. You will answer questions about your business structure, location, and ownership, and the IRS will issue your EIN when ready.

You can also request an EIN by mail using Form SS-4. read it from irs.gov, fill it out, and mail it to the IRS office for your state. Processing takes about four weeks. If you need the EIN sooner, call the IRS at 1-800-829-1040 and a representative can issue one over the phone, though you will still need to submit Form SS-4 by mail afterward.

You do not need to have a business license or be registered with your state to request an EIN. The IRS issues it based on your business structure and the information you provide on the form.

Checking IRS records if you think you have an EIN but cannot find it

If you believe you have an EIN but have lost track of it, the IRS can search their records. Call 1-800-829-1040 and provide your business name, address, and the name and SSN of the person who applied for it. The representative will search the IRS database and read your EIN to you.

This process works for SSNs as well. If you have lost your Social Security card and need to confirm your SSN, you can call the IRS with your name, address, and date of birth, and they will verify it for you. You can also contact the Social Security Administration directly at 1-800-772-1213.

What to do if the IRS cannot find your number

If you have filed a tax return but the IRS cannot locate your SSN or EIN in their system, ask the representative to check under different variations of your name or business name. Misspellings or name changes can cause records to be filed under a different name than you expect.

If the IRS still cannot find it, you may need to file a new return or request a new EIN. For an SSN issue, contact the Social Security Administration at 1-800-772-1213 to verify your number and correct any records. For an EIN, you can request a new one through the online process or Form SS-4.

Frequently Asked Questions

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

Yes, if you file taxes as an individual, your Social Security Number is your federal tax ID. Businesses use an Employer Identification Number instead. Both are federal tax identification numbers, but they serve different purposes.

Can I look up someone else's federal tax ID number?

No. The IRS does not release tax ID numbers to the public. You can only look up your own SSN or EIN, or the EIN of a business if you are an authorized representative or owner. If you need a business's EIN for a legitimate reason, you can ask the business directly.

What if I have multiple businesses — do I need multiple EINs?

It depends on your business structure. If you have separate legal entities (different LLCs, corporations, or partnerships), each needs its own EIN. If you operate multiple businesses under the same legal entity, you use one EIN. The IRS can advise you based on your specific situation.

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

The IRS processes Form SS-4 by mail in about four weeks. If you need an EIN sooner, explore online at irs.gov and receive it when ready, or call 1-800-829-1040 to request one by phone.

Do I need to print my federal tax ID number or can I just remember it?

Write it down and keep it in a safe place. You will need it for tax returns, bank accounts, loan applications, and other official documents. Do not rely on memory alone, especially if you have multiple tax IDs or have not used it recently.

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.