How to Find Your Business Tax ID Number

Where to look for your EIN if you already have one

Your business tax ID number — officially called an Employer Identification Number (EIN) — appears on several documents you likely already have. Check your most recent tax return first: the EIN is printed at the top of Form 1040-C (sole proprietor), Form 1120 (corporation), or Form 1065 (partnership). If you filed taxes through a CPA or accountant, ask them directly — they have the number on file.

Look at your business bank account paperwork and loan documents next. Banks require the EIN when you open a business account, so it will be on your account setup forms and statements. If you have an IRS notice, letter, or bill related to your business, the EIN appears there too. The IRS also sends an official SS-4 confirmation letter when you first receive your EIN; if you kept that letter, the number is printed clearly at the top.

If you cannot find the number through those routes, you can retrieve it directly from the IRS. Call the IRS Business and Specialty Tax Line at 800-829-4933 during business hours (Monday through Friday, 7 a.m. to 7 p.m. your local time). Have your Social Security number and the business name and address ready. The IRS will confirm your EIN over the phone.

Key Takeaways

Your EIN appears on your business tax returns, bank account paperwork, and any IRS letters sent to your business.
If you filed taxes with a CPA or accountant, they have your EIN on file and can provide it when ready.
The IRS can confirm your EIN by phone at 800-829-4933 if you have your Social Security number and business address ready.
If you have never received an EIN, you will need to request one from the IRS using Form SS-4.

What to do if you never received an EIN

Some business owners think they have an EIN but never actually received one. This happens when a business was started informally or when the person who originally set it up did not complete the registration. If you cannot find your EIN through any of the methods above, you likely do not have one yet.

To request an EIN, you will need to file Form SS-4 with the IRS. You can do this online through the IRS website (irs.gov), by mail, by fax, or by phone. The online method is fastest: you fill out the form on the IRS website, and the system issues your EIN when ready. By phone, you call 800-829-4933 and an IRS representative fills out the form with you; you receive the number at the end of the call. By mail or fax, processing takes about four weeks.

You will need your Social Security number, the business name, the business address, the type of business structure (sole proprietor, LLC, corporation, partnership), and the date you started or plan to start the business. If your business has employees or you plan to hire them, have that information ready too.

Using the IRS online search tool

The IRS does not have a public search tool where you can look up an EIN by business name. However, if you are the business owner or an authorized representative, you can retrieve your EIN by calling the IRS directly. The phone method is the fastest way to confirm a number you think you have or to get a number you have lost.

Some third-party websites claim to search EIN records, but these are not official IRS tools and often charge a fee for information that the IRS provides free. Stick with the IRS phone line or the official IRS website to avoid scams and unnecessary costs.

What you need before you call the IRS

When you call 800-829-4933 to retrieve your EIN, have these items ready: your Social Security number, the business name exactly as it appears on your tax return or business registration, the business address, and the phone number associated with the business if you have one. The IRS representative will ask for this information to confirm your identity and locate your account.

Call during business hours: Monday through Friday, 7 a.m. to 7 p.m. in your time zone. Wait times are usually shorter early in the morning or late in the afternoon. If you are calling from outside the United States, use the international number listed on the IRS website for your country.

EIN vs. Social Security number for tax purposes

If your business is a sole proprietorship with no employees, you may use your Social Security number instead of an EIN on your tax return. However, most business owners get an EIN anyway because it keeps your personal and business finances separate on IRS records and protects your Social Security number from being shared with vendors and banks.

If you have employees, you must have an EIN — you cannot use your Social Security number. The same is true if your business is structured as an LLC, S-corporation, C-corporation, or partnership. Even if you are not required to have an EIN, getting one is free and takes minutes, so most business owners do it regardless of their business structure.

Keeping your EIN safe and accessible

Once you have your EIN, write it down and store it somewhere you can find it again. Many business owners keep a copy in a folder with their other tax documents, in their business bank account file, or in a password-protected digital file. You will need it every year for your tax return, when you open a business bank account, when you explore for business loans or credit, and when you hire employees.

Do not share your EIN with anyone except your accountant, your bank, your employer (if you are an employee of another business), or government agencies that request it. Treat it like you would treat a Social Security number — it is a unique identifier tied to your business finances.

Frequently Asked Questions

Can I look up someone else's EIN?

No. The IRS does not release EIN information to the public. You can only retrieve your own EIN or an EIN for a business you own or are authorized to represent. If you need an EIN for business purposes (like verifying a vendor), ask the business directly.

What if I lost my EIN and cannot remember my business name?

Call the IRS at 800-829-4933 with your Social Security number and the business address. The IRS can search by address and Social Security number if you cannot remember the exact business name. Have your phone number and any other business details ready to help them locate your account.

How long does it take to get an EIN?

Online through the IRS website, you receive your EIN when ready. By phone, you get it at the end of the call. By mail or fax, processing takes about four weeks. If you need the number urgently, use the online or phone method.

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

You are not required to have one, but it is recommended. You can use your Social Security number on your tax return instead, but an EIN keeps your personal and business finances separate on IRS records and is free to obtain.

What if the IRS says they have no record of my EIN?

This can happen if the form was never processed or if there was an error in the original filing. Ask the IRS representative to help you file a new Form SS-4. You will receive a new EIN, and the IRS can explain what happened to the original 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.