How to Find Your Business Federal Tax ID Number

Where to look for 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, it will appear on several documents you likely already have. Check your IRS correspondence first — any letter from the IRS about your business will display your EIN at the top.

Look through your business records for the IRS Form SS-4 confirmation letter, which is the official document the IRS sends after assigning your EIN. Your bank may also have it on file; call your business account manager and ask them to confirm your EIN. If you filed business tax returns, your EIN appears on the first page of every return you submitted.

If you cannot locate the original paperwork, the IRS can tell you your EIN over the phone. Call the Business and Specialty Tax Line at 1-800-829-4933 during business hours. Have your Social Security Number, business name, and business address ready. The IRS will not email or mail your EIN to you — they will only read it to you during the call.

Key Takeaways

Your EIN appears on IRS letters, your Form SS-4 confirmation, bank records, and any business tax returns you have filed.
If you cannot find your EIN in your records, call the IRS Business and Specialty Tax Line at 1-800-829-4933 with your Social Security Number and business address ready.
The IRS will read your EIN to you over the phone but will not send it by email or mail as a replacement for a lost letter.
If you never received an EIN, you may need to request one through Form SS-4 or the IRS online system, depending on your business structure.

How to request an 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 the IRS online system at irs.gov/ein. You will need your Social Security Number, business name, business address, and information about your business structure (sole proprietorship, partnership, corporation, or LLC). The online system assigns your EIN immediately after you complete the form, and you can print a confirmation page on the spot.

If you prefer to apply by mail or fax, you can submit Form SS-4 (Application for an Employer Identification Number) to the IRS. Mail takes about four weeks; fax takes about two weeks. You will need the same information as the online method. The IRS will mail you a confirmation letter with your new EIN.

If you are applying by phone, call 1-800-829-4933 and speak with an IRS representative. They will ask you the same questions and assign your EIN during the call. You can request that they mail a confirmation letter afterward, though it may take several weeks to arrive.

What information you need to have ready

Before you contact the IRS or use their online system, gather these documents and details. You will need your Social Security Number or Individual Taxpayer Identification Number (ITIN). You will also need your legal business name exactly as it appears on your business registration or formation documents.

Have your business mailing address ready — this is the address where the IRS will send mail about your business. If your business operates from your home, use your home address. You will also need to know your business structure: are you a sole proprietor, a partnership, a corporation, an LLC, or something else? The IRS asks this question on every application method.

If your business has a specific business purpose or industry (retail, consulting, manufacturing, nonprofit, etc.), have that ready as well. The IRS uses this information to assign the correct tax classification, though it does not affect whether you receive an EIN.

Timeline for receiving your EIN

The speed of receiving your EIN depends on which method you use. The online system at irs.gov/ein is the fastest — you receive your EIN immediately and can print a confirmation page before you leave the website. This method works during business hours, Monday through Friday.

Phone requests take one business day. When you call 1-800-829-4933, the IRS representative assigns your EIN during the call and reads it to you. They can mail a confirmation letter, but that letter may take two to four weeks to arrive.

Fax requests take about two weeks from the date the IRS receives your Form SS-4. Mail requests take about four weeks. If you need your EIN quickly for banking or vendor purposes, use the online system or phone method rather than mail or fax.

Using your EIN once you have it

Once you have your EIN, you will use it on business tax returns, payroll documents, and bank account applications. When you open a business bank account, the bank will ask for your EIN. When you hire employees, you will need your EIN to file payroll tax forms with the IRS.

If you are a sole proprietor with no employees, you may not need an EIN for tax purposes — you can use your Social Security Number instead. However, many banks and vendors require an EIN even for sole proprietorships, so it is often worth obtaining one regardless.

Keep your EIN in a safe place with your other business documents. You will need it for years, and losing it means calling the IRS again to retrieve it. Write it down in multiple locations or store it in a secure digital file.

Common reasons the IRS cannot find your EIN

If you call the IRS and they cannot locate your EIN, it may be because you provided incorrect information. The IRS matches your request against their records using your Social Security Number, business name, and business address. If any of these details do not match exactly what they have on file, their system will not find it.

If your business name has changed since you received your EIN, tell the IRS the old name as well as the new one. If you moved your business address, provide both the old and new addresses. If you are unsure of the exact spelling or format the IRS has on file, ask the representative to search using your Social Security Number alone.

If the IRS still cannot find your EIN after multiple calls, it is possible your original application was never processed. In that case, you can submit a new Form SS-4 application. The IRS will issue a new EIN, and you can use that going forward.

Frequently Asked Questions

Can I look up my EIN online without calling the IRS?

The IRS does not have a public lookup tool for EINs. You must call 1-800-829-4933, use the online Form SS-4 system to request a new one, or check your own business records. If you have filed business tax returns, your EIN is on those returns.

What if I lost my EIN confirmation letter?

Call the IRS at 1-800-829-4933 with your Social Security Number and business address. They will read your EIN to you over the phone. You can request a replacement confirmation letter, though it may take several weeks to arrive by mail.

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

Not for tax purposes — you can use your Social Security Number instead. However, most banks require an EIN to open a business account, and many vendors prefer it. It is often simpler to obtain one even if you are not required to have one.

How long does it take to get an EIN by mail?

The IRS typically processes mailed Form SS-4 applications within four weeks. If you need your EIN faster, use the online system (immediate) or call the IRS (same day).

Can someone else call the IRS to find my business EIN?

No. The IRS will only provide your EIN to you or an authorized representative with a power of attorney on file. If you need someone else to handle this, you must file Form 2848 (Power of Attorney and Declaration of Representative) with the IRS first.

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.