How to Find Your Business Tax ID Number

Where to Look for Your Business Tax ID

Your business tax ID—officially called an Employer Identification Number (EIN)—is a nine-digit number the IRS assigns to your business. If you received one, it will appear on documents you got from the IRS, not on your business license or state registration. The fastest way to find it is to check the paperwork you received when you first set up your business.

Look through your files for IRS Form SS-4 confirmation letter, which the IRS mailed to you after you requested an EIN. This letter has your EIN printed clearly at the top. If you filed your first business tax return, your EIN appears on that return as well. You can also find it on any correspondence the IRS has sent you about your business account.

If you cannot locate the original paperwork, the IRS website has a lookup tool that works if you have the correct legal business name and the address where you registered the business. You will need to verify your identity through their online system before they show you the number.

Key Takeaways

Your EIN is a nine-digit number assigned by the IRS, found on Form SS-4 confirmation letters or your first business tax return.
The IRS online EIN lookup tool lets you search by business name and address if you cannot find your original paperwork.
You will need to verify your identity through the IRS website before they display your EIN in the lookup tool.
If you never received an EIN, you can request one through the IRS website or by mailing Form SS-4 to your regional IRS office.
Your bank, accountant, or payroll provider may have a copy of your EIN on file if you have worked with them.

Using the IRS Online Lookup Tool

The IRS offers a free online tool called the EIN Lookup on their website at irs.gov. To use it, you will need the legal name of your business exactly as it appears on your IRS registration, the business address, and the name and Social Security number of the person who requested the EIN originally (usually the owner or responsible party).

Go to the IRS website, navigate to the EIN section, and select the option to look up an existing EIN. Enter your information and complete the identity verification steps. The system will ask you security questions based on your credit history or other records to confirm you are authorized to view the EIN. Once verified, the system displays your nine-digit number on screen.

Write down the number as soon as you see it, or take a screenshot. The IRS does not email the result to you, so you will need to record it yourself during that session.

Checking With Your Bank or Accountant

If you set up a business bank account, your bank has your EIN on file. Call the business banking department and provide your account number and business name. They can confirm your EIN over the phone or in writing. This is often the fastest option if you have an active business account.

Your accountant or bookkeeper also has your EIN recorded in your business file. If you have worked with a tax professional, send them an email or call and ask them to provide it. They can usually give you the number within a day.

Your payroll provider, if you use one, will have your EIN as well. Check any payroll documents or login to your payroll account online to find it listed under your business information.

What to Do If You Never Received an EIN

If you requested an EIN but never received a confirmation letter, the IRS may not have processed your request or the letter may have been lost in the mail. You can request a new EIN through the IRS website or by phone. The phone line for EIN requests is available Monday through Friday, 7 a.m. to 10 p.m. Eastern time.

To request an EIN by mail, fill out Form SS-4 and send it to the IRS office that serves your state. The IRS will mail you a confirmation letter with your new EIN within two to four weeks. You can also request an EIN in person at your local IRS office if you prefer to handle it face-to-face.

If you are requesting an EIN for the first time, you will need to provide your business structure (sole proprietorship, partnership, corporation, LLC), the business address, and the name and Social Security number of the owner or responsible party.

Understanding Your EIN vs. Other Business Numbers

Your EIN is different from your state business license number, your Doing Business As (DBA) registration number, or your state tax ID. Each of these is a separate identifier issued by different agencies. Your EIN is federal and issued by the IRS only. Your state tax ID is issued by your state's revenue or taxation department and is used for state income tax and sales tax purposes.

If you are self-employed and operate as a sole proprietor without employees, you may not have an EIN at all—you would use your Social Security number for federal tax purposes instead. However, if you have employees, operate as a corporation or LLC, or want a separate business tax account, you need an EIN.

Do not confuse your EIN with your DUNS number, which is issued by Dun & Bradstreet and used for business credit reporting. The DUNS number is optional and separate from your IRS EIN.

Keeping Your EIN Safe and Accessible

Once you find your EIN, store it in a find location where you can find it quickly when you need it. Keep a copy in your business files, your accounting software, and with your important documents. You will need it every time you file a business tax return, set up a business bank account, hire employees, or explore for business licenses or permits.

Do not share your EIN publicly or with people who do not have a legitimate business reason to see it. Treat it like you would treat a Social Security number—it is sensitive business information. If you suspect your EIN has been misused or compromised, contact the IRS when ready.

Frequently Asked Questions

Can I look up someone else's business EIN?

The IRS lookup tool requires you to verify your identity and typically works only if you are the business owner or authorized representative. You cannot use it to look up another person's EIN without their permission. If you need a business's EIN for legitimate purposes, ask the business owner or manager directly.

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

Yes. Each separate business entity gets its own EIN. If you own two LLCs, a sole proprietorship, and a corporation, each one has a different nine-digit number. You request a separate EIN for each business structure through Form SS-4.

How long does it take to get an EIN if I request one now?

If you request an EIN online through the IRS website, you receive the number when ready after verification. If you mail Form SS-4, expect two to four weeks. Phone requests are processed the same day you call during business hours.

Do I need an EIN if I am a sole proprietor with no employees?

Not required by law. You can use your Social Security number for federal tax purposes. However, many sole proprietors request an EIN anyway to keep their personal and business finances separate and to build business credit.

What should I do if the IRS lookup tool says my EIN does not exist?

Double-check that you entered your legal business name and address exactly as they appear on your IRS registration. If the information is correct and the tool still shows no result, contact the IRS directly by phone or visit a local IRS office. Your EIN may be under a different business name or address than you remember.

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.