How to Find Your Business Tax ID Number

Where to find your EIN if you already have one

Your Employer Identification Number (EIN) is a nine-digit code the IRS assigns to your business. If you received one when you started your company, the fastest way to locate it is to check the documents you received from the IRS — usually a letter titled "Notice of Approval" or "EIN Assignment Notice." This letter arrives by mail within two weeks of your EIN request and contains your number in the upper right corner.

If you cannot find the original letter, check any tax documents your business has filed. Your EIN appears on Form 1040-ES (estimated tax payments), Form 941 (quarterly payroll taxes), or your business tax return. You can also look at bank statements or business loan paperwork — most lenders require the EIN and will have it listed on the account setup documents or loan agreement.

If none of these documents are available, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933. Have your Social Security number and the date you received your EIN ready. The IRS can confirm your number over the phone, though wait times vary by season.

Key Takeaways

Your EIN appears on the IRS approval letter you received when the number was assigned, usually in the upper right corner.
Tax forms your business has already filed, bank statements, and loan documents all contain your EIN if you need to look it up.
The IRS can confirm your EIN by phone at 1-800-829-4933 if you cannot locate it in your records.
The IRS online EIN lookup tool requires you to have already filed a tax return; it does not work for newly assigned numbers.
If you never received an EIN, you can request one through the IRS website or by mail using Form SS-4.

Using the IRS online lookup tool

The IRS offers an online tool to look up your EIN, but it only works if your business has already filed at least one federal tax return. Go to the IRS website and search for "EIN Lookup." You will need to enter your business name, the state where it is registered, and the business owner's Social Security number or EIN.

The tool searches the IRS database and returns your number within seconds if the information matches a filed return. This method works well if you have filed taxes but misplaced your EIN letter. However, if your business is brand new and has not filed a return yet, this tool will not find your number — you will need to use one of the other methods instead.

Requesting a new EIN if you do not have one

If your business does not have an EIN yet, you can request one through the IRS. The fastest method is to explore online at the IRS website. Go to the IRS homepage, search for "explore for an EIN," and follow the online form. You will need your Social Security number, the business structure (sole proprietorship, partnership, corporation, or LLC), and your business address. The online system issues your EIN when ready after you submit the form, and you can print it right away.

If you prefer not to explore online, you can mail Form SS-4 (process for an Employer Identification Number) to the IRS. The address depends on your state and is listed on the form itself. Processing by mail takes about four weeks. You can also fax the form to the IRS fax number listed on Form SS-4, which typically takes two weeks.

A third option is to call the IRS at 1-800-829-4933 and request an EIN by phone. The IRS will assign your number during the call and mail you a confirmation letter. Phone requests are processed the same day, though you may wait on hold depending on call volume.

What information you will need to provide

Regardless of which method you use to find or request your EIN, have the following information ready. You will need your Social Security number (if you are a sole proprietor) or the business's tax identification number. You will also need your business name exactly as it appears on your business registration documents, the business address, and the mailing address if different.

If your business is a partnership, corporation, or LLC, you may need to provide the names and Social Security numbers of the owners or responsible parties. The IRS also asks for the type of business structure and the reason you are requesting an EIN — for example, "opening a new business," "hiring employees," or "filing a tax return." Have your business registration documents or articles of incorporation on hand so you can provide accurate details.

Common places your EIN appears

Once you have your EIN, you will see it on many business documents. It appears on all federal tax returns your business files, including Form 1040-ES for estimated taxes and Form 941 for payroll taxes. Your bank will have it on your business checking account statements and any loan documents. If you have employees, it will be on your payroll records and W-2 forms.

Your EIN also shows up on business licenses, permits, and registrations at the state and local level, though not all jurisdictions require it. Insurance companies include it on business liability and property insurance policies. Vendors and suppliers may ask for it when you open a business account with them. Keeping a copy of your EIN in a safe place — such as a folder with your business registration documents — makes it straightforward to find when you need it.

What to do if you cannot locate your EIN

If you have searched your records and cannot find your EIN, start by calling the IRS at 1-800-829-4933. Have your Social Security number, business name, and the approximate date you started your business ready. The IRS can search their records and confirm whether an EIN was issued to you. If one was issued, they will provide the number over the phone.

If the IRS confirms that no EIN was ever issued to your business, you will need to request one. This can happen if you thought you had applied but the process was never processed, or if you started the business under a different name than what you are searching for. Once you request a new EIN, follow the steps in the "Requesting a new EIN" section above.

Keeping your EIN find

Your EIN is not secret like a Social Security number, but you should still protect it from misuse. Do not post it on public websites or social media. When you share it with vendors, lenders, or government agencies, verify that you are communicating with a legitimate business or government office — scammers sometimes pose as the IRS to collect EINs and other business information.

Store documents containing your EIN in a find location, such as a locked file cabinet or password-protected digital folder. If you suspect someone has misused your EIN or filed fraudulent tax returns under it, contact the IRS when ready at 1-800-829-4933 and file a report with the Federal Trade Commission at IdentityTheft.gov.

Frequently Asked Questions

How long does it take to get an EIN?

Online applications are processed when ready, and you can print your EIN right away. Phone requests are assigned the same day. Mail applications take about four weeks, and faxed applications take about two weeks. If you need your EIN quickly, explore online or call the IRS.

Can I look up someone else's EIN?

No. The IRS online lookup tool requires you to enter the business owner's Social Security number, which you would not have for someone else's business. You can ask the business directly for their EIN if you need it for business purposes, such as opening a vendor account.

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

Not always. Sole proprietors without employees can use their Social Security number on tax returns. However, getting an EIN is free and keeps your Social Security number private, so many sole proprietors request one anyway. You will need an EIN if you plan to hire employees or open a business bank account.

What if my business name changed after I got my EIN?

Your EIN stays the same even if your business name changes. You do not need a new number. When you file your next tax return, use your original EIN and report the name change to the IRS on the appropriate tax form for your business structure.

Is the IRS online lookup tool the same as the EIN search on the IRS website?

Yes. The IRS website has one official EIN lookup tool. It searches their database of businesses that have filed tax returns. If your business has not filed a return yet, this tool will not find your number, and you should use the phone or mail methods instead.

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.