Where to find your Tax ID number

Your Tax ID number is printed on documents the IRS has already sent you. The fastest way to find it is to look at a past tax return, a W-2 form from an employer, a 1099 form from a client or bank, or a letter from the IRS. If you have filed taxes before, any of these will show your number in the same place every time.

If you do not have any of those documents, you can call the IRS directly at 1-800-829-1040. Have your name, date of birth, and current address ready. The IRS will confirm your number over the phone. Wait times are longest during tax season (January through April), so calling in other months is faster.

If you are self-employed or run a business, your Tax ID might be an Employer Identification Number (EIN) instead of a Social Security number. An EIN is a nine-digit number the IRS assigns to businesses. You can look it up on the IRS website using the EIN Lookup Tool at irs.gov, or call the IRS Business and Specialty Tax Line at 1-800-829-4933.

Key Takeaways

  • Your Tax ID number appears on any tax return you have filed, any W-2 or 1099 form you received, or any letter from the IRS.
  • If you cannot find a document, call the IRS at 1-800-829-1040 with your name, date of birth, and address.
  • Self-employed people and business owners may have an EIN (Employer Identification Number) instead of using a Social Security number as their Tax ID.
  • The IRS EIN Lookup Tool at irs.gov lets you search for a business Tax ID without calling.

What documents show your Tax ID number

A Form 1040 (the main individual tax return form) displays your Tax ID in the top right corner. A W-2 form (wage and income statement from an employer) shows it in box a. A 1099 form (income from self-employment, freelance work, or interest) shows it in the top left. Any IRS letter or notice you received will have your number printed near the top.

If you filed taxes jointly with a spouse, both Social Security numbers appear on the return. If you need only your own number, look for the one listed first on a joint return, or call the IRS to confirm which is yours.

If you have never filed a tax return and do not have a Tax ID yet, you will need to obtain one before you can file. The process depends on whether you are a U.S. citizen, a resident alien, or a non-resident alien, and the IRS website has separate instructions for each.

Using the IRS phone line

Call 1-800-829-1040 Monday through Friday, 7 a.m. to 7 p.m. your local time. Have ready: your full name exactly as it appears on your tax return, your date of birth, your current mailing address, and a phone number where you can be reached. The IRS representative will confirm your Tax ID over the phone and may ask security questions to verify your identity.

If you are calling about a business EIN, use 1-800-829-4933 instead. That line handles questions about Employer Identification Numbers and business tax accounts. Both lines are free.

Wait times vary by time of day and season. Early morning calls (before 10 a.m.) and calls made outside tax season typically have shorter waits. If you reach a busy signal, try again later rather than waiting on hold.

Looking up an EIN online

If you own a business and need to find your Employer Identification Number, go to irs.gov and search for "EIN Lookup." The IRS provides a tool where you enter your business name and address. The tool returns the EIN if the business is registered with the IRS.

You will need the exact legal name of the business as it was registered with the IRS, and the address where the business is located. If the business has moved or changed its legal name, the lookup may not find it. In that case, call 1-800-829-4933 with your business information and the IRS can search their records.

An EIN is a nine-digit number formatted as XX-XXXXXXX. It is different from a Social Security number and is used only for business and tax purposes.

What to do if you cannot find your number

If you have looked through old tax documents and cannot locate your Tax ID, the IRS phone line is your most direct option. You do not need to have filed taxes before to get your number — if you have a Social Security number, that is your Tax ID for individual purposes. The IRS can confirm it by phone.

If you have never had a Social Security number and are not a U.S. citizen, you may need to apply for an Individual Taxpayer Identification Number (ITIN) instead. The process is different and requires Form W-7. The IRS website has instructions for non-citizens and resident aliens.

Keep a record of your Tax ID once you have found it. Write it down in a safe place, or save a photo of a document that shows it. You will need it for tax returns, opening bank accounts, and other financial matters.

Frequently Asked Questions

Is my Tax ID the same as my Social Security number?

For most people, yes. Your Social Security number is your Tax ID for individual tax purposes. If you are self-employed or own a business, you may also have an EIN, which is a separate nine-digit number used only for business taxes.

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

No. Tax ID numbers are private information protected by law. The IRS will only confirm a Tax ID to the person it belongs to, or to an authorized representative with power of attorney. You cannot look up another person's number online or by phone.

What if I lost my Social Security card and do not remember my number?

Call the IRS at 1-800-829-1040 with your name, date of birth, and address. They will confirm your Social Security number. You can also contact the Social Security Administration at 1-800-772-1213 to request a replacement card or to confirm your number.

Do I need my Tax ID to file taxes online?

Yes. Tax filing software and the IRS website both require your Tax ID before you can file. If you do not have it, find it using one of the methods above before you start the filing process.