How to Find Your Business Tax ID Number

Where to find your EIN or 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 have it, it will be in one of three places: a letter from the IRS you received when you first got the number, your business tax returns from prior years, or your business bank account paperwork.

If you cannot find it in those places, the IRS has a tool called the EIN Lookup on their website at irs.gov. You will need your business name, the address where you registered it, and the date you received the EIN. The lookup returns your number when ready.

If you do not have an EIN yet and need one, you can request one from the IRS for free. The process takes about 15 minutes if you explore online, or you can call the IRS Business and Specialty Tax Line at 1-800-829-4933 during business hours.

Key Takeaways

Your EIN is a nine-digit number issued by the IRS and appears on prior tax returns, IRS letters, and business bank account documents.
The IRS EIN Lookup tool on irs.gov lets you search for your number using your business name, registration address, and the year you received it.
If you do not have an EIN, you can request one online at irs.gov in about 15 minutes, or by phone at 1-800-829-4933.
You will need your EIN to file business taxes, hire employees, open a business bank account, and explore for business licenses or loans.

Checking your prior tax documents

The fastest way to locate your EIN is to look at any business tax return you filed in the past. Your EIN appears at the top of Form 1040-C (if you are a sole proprietor), Form 1065 (partnership), Form 1120 (corporation), or Form 1120-S (S corporation). If you filed taxes last year or the year before, pull that return from your files or ask your accountant for a copy.

Your EIN also appears on any quarterly estimated tax payment records you sent to the IRS, and on correspondence from the IRS about your account. If you have a business accountant or bookkeeper, they will have your EIN on file and can tell you the number in seconds.

Using the IRS EIN Lookup tool

Go to irs.gov and search for "EIN Lookup." The tool is free and does not require you to log in. You will enter your business legal name exactly as it appears on your IRS records, the street address where your business is registered, and the year you received the EIN (or your best guess if you are not sure).

The lookup returns your nine-digit number within seconds. Write it down or take a screenshot. This tool works whether your business is a sole proprietorship, partnership, corporation, or nonprofit — as long as the IRS issued you an EIN, the lookup will find it.

If the lookup does not return a result, your business may not have an EIN yet, or you may have entered the business name or address differently than it appears in IRS records. Try variations of your business name (with or without "LLC," "Inc.," or "Company," for example) or call the IRS at 1-800-829-4933 to confirm.

Requesting a new EIN if you do not have one

If your business does not have an EIN yet, you can request one online at irs.gov. Go to the IRS website, search for "explore for an EIN," and follow the online form. You will need your Social Security number or ITIN, your business legal name, the business address, and the type of business structure (sole proprietor, LLC, corporation, etc.). The process takes about 15 minutes and you receive your EIN when ready.

You can also request an EIN by phone. Call the IRS Business and Specialty Tax Line at 1-800-829-4933 Monday through Friday, 7 a.m. to 7 p.m. your local time. Have your Social Security number and business information ready. The IRS agent will issue your number over the phone and mail you a confirmation letter.

If you are explore for an EIN as a foreign business or nonprofit, you will need to mail Form SS-4 to the IRS instead of explore online. The IRS website has instructions for mailing the form and the address to send it to.

What you will need your EIN for

Your EIN is required to file business income taxes with the IRS. You also need it to hire employees, open a business bank account, and explore for a business license or permit in most states. Many lenders and vendors will ask for your EIN before they extend credit or enter into a contract with your business.

If your business is a partnership, corporation, S corporation, or LLC with multiple owners, you must have an EIN. Sole proprietors can use their Social Security number for some purposes, but the IRS recommends getting an EIN to keep your personal and business finances separate.

If you lost your EIN letter from the IRS

The IRS mails you a letter (Form SS-4) when you first receive your EIN. If you lost that letter, you do not need to request a new EIN — you already have one. Use the EIN Lookup tool described above to find your number, or call 1-800-829-4933 and ask the IRS to mail you a replacement letter showing your EIN.

The IRS can also provide your EIN over the phone if you call during business hours. Have your business name, address, and Social Security number ready. The agent will confirm your EIN and can mail you a new letter if you need one for a bank or lender.

Frequently Asked Questions

Can I look up someone else's business EIN?

No. The EIN Lookup tool requires you to enter the business name and address, and it only returns the EIN to the person who owns or is authorized to represent that business. You cannot use it to search for a competitor's or stranger's EIN. If you need a business's EIN for a legitimate reason (you are a vendor or lender), ask the business directly.

What if the EIN Lookup tool says my business does not have an EIN?

Your business may not have been assigned an EIN yet, or you may have entered the name or address differently than the IRS has it on file. Try searching with variations of your business name, or call 1-800-829-4933 to confirm whether an EIN exists. If it does not, you can request one online or by phone.

Do I need a separate EIN for each business I own?

Yes. Each separate business entity needs its own EIN. If you own two LLCs or a sole proprietorship and a corporation, each one gets a different nine-digit number. The IRS uses the EIN to track income and taxes for each business separately.

How long does it take to get an EIN?

If you explore online, you receive your EIN when ready. If you explore by phone, the IRS agent issues it during the call. If you mail Form SS-4, allow four to six weeks for the IRS to process it and mail you a confirmation letter.

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.