How to Find a Business Employer Identification Number: Step-by-Step Guide (2026)

The short answer: You can find a business Employer Identification Number (EIN) by checking the IRS confirmation letter (CP 575) or Form SS-4 you received when the EIN was issued, reviewing old business tax returns and bank or loan documents, or calling the IRS Business and Specialty Tax Line at 1-800-829-4933. The IRS does not publish a public EIN lookup database, so the owner or an authorized representative must retrieve it directly.

What Is an Employer Identification Number?

An Employer Identification Number, or EIN, is a nine-digit federal tax ID issued by the IRS, formatted as XX-XXXXXXX. Think of it as a Social Security number for a business. Sole proprietors with no employees can often use their personal SSN, but corporations, partnerships, LLCs with employees, and trusts generally need an EIN to file taxes, open business bank accounts, hire employees, and apply for business licenses and loans.

Where to Find Your EIN: Check Your Own Records First

Before calling anyone, search your own files. The fastest way to find a business EIN is almost always in paperwork you already have.

• IRS confirmation letter (CP 575): When the IRS issues an EIN, it sends a confirmation notice, CP 575, showing the number. This is the most reliable source. If you applied online, you may also have a PDF confirmation saved from the application session.
• Form SS-4: The Application for Employer Identification Number itself lists the EIN on the finalized copy. Check your records for the completed form.
• Business tax returns: Your EIN appears at the top of every federal business tax return, including Form 1120, 1120-S, 1065, and Schedule C of Form 1040.
• Bank and loan documents: Business bank account applications, loan agreements, and merchant account paperwork all record the EIN used to open the account.
• State filings: Business licenses, articles of incorporation, and annual reports filed with your state often include the EIN.
• Payroll records: If you have employees, the EIN appears on payroll tax filings, Form 941, W-2s, and 1099s issued under the business.

Step-by-Step: How to Retrieve a Lost EIN from the IRS

If your own records turn up nothing, the IRS can provide the number, but only to the right person.

Step 1: Confirm you are authorized to ask

The IRS will only give an EIN to the business owner, a partner, a corporate officer, or another authorized representative, such as someone with a valid Power of Attorney (Form 2848). You cannot retrieve another company’s EIN this way.

Step 2: Gather your identifying information

Before calling, have the legal business name, the business address on file, the type of entity, and the responsible party’s name and SSN or ITIN ready. The IRS agent will use these to verify your identity and locate the account.

Step 3: Call the IRS Business and Specialty Tax Line

Call 1-800-829-4933, Monday through Friday, 7 a.m. to 7 p.m. local time. After identity verification, the agent can provide the EIN over the phone. Ask them to also confirm the mailing address on file is current so future notices reach you.

Step 4: Request a replacement confirmation letter

While on the call, ask for a replacement CP 575 notice or a Letter 147C, which officially confirms the EIN. Keep this document in a safe place so you never have to repeat the process.

How to Find Another Business’s EIN

There is no official public EIN lookup tool, but there are legitimate ways to find a business EIN when you need one, for example to issue a 1099 or verify a vendor.

Ask the business directly

The simplest route is asking. Businesses routinely share their EIN on a completed Form W-9, which is the standard document for collecting tax IDs from vendors and contractors. If you are paying a business, request a W-9 before you pay.

Check public filings

Nonprofits must disclose their EIN on IRS Form 990, which is publicly searchable through the IRS Tax Exempt Organization Search. Publicly traded companies include their EIN on SEC filings such as the annual 10-K, available on the SEC’s EDGAR database. Some state business-entity searches also display EINs.

Use commercial EIN lookup services with caution

Several paid databases sell EIN lookup services. These can work for basic verification, but their data may be outdated or incomplete, and you should never rely on one for tax filing without confirming the number with the business itself.

Common EIN Mistakes to Avoid

• Applying for a new EIN when you lost the old one: Do not apply for a second EIN just because you cannot find the first. The IRS expects one EIN per business entity, and a duplicate creates tax filing confusion. Retrieve the original instead.
• Using the wrong EIN on tax returns: Filing under the wrong EIN triggers IRS notices and delays refunds. Double-check the number against your CP 575 letter before filing.
• Sharing your EIN carelessly: Treat an EIN like a sensitive ID. Share it only with banks, the IRS, and legitimate business partners. EIN fraud, where criminals use a business’s EIN to file fake returns or open credit, is a real problem.
• Assuming the number changed: An EIN generally stays with the business for its lifetime. Name changes, address changes, and ownership changes within the same entity do not create a new EIN in most cases.

Further Reading

• How to Buy a House: Step-by-Step Guide (2026)
• How to Write a Check: Step-by-Step Guide (2026)
• How to Pay Off Credit Card Debt: Step-by-Step Guide (2026)
• CFPB’s Ask CFPB resource
• Internal Revenue Service

Frequently Asked Questions

Can I look up an EIN online for free?

There is no official IRS tool for looking up your own EIN online. Nonprofit EINs can be found free through the IRS Tax Exempt Organization Search, and public company EINs appear in SEC filings, but for a private business you must check your own records or call the IRS.

What is the IRS phone number to find a lost EIN?

Call the IRS Business and Specialty Tax Line at 1-800-829-4933, Monday through Friday from 7 a.m. to 7 p.m. local time. Have the business name, address, entity type, and the responsible party’s identification ready for verification.

How long does it take to get a replacement EIN letter?

The IRS can give you the EIN number itself over the phone the same day. A replacement confirmation letter, such as Letter 147C, typically arrives by mail within a few weeks of your request.

Do I need an EIN for my LLC?

Most LLCs need an EIN, especially multi-member LLCs, LLCs with employees, and LLCs taxed as corporations. A single-member LLC with no employees can use the owner’s SSN in some cases, but getting an EIN is still recommended because banks and vendors often require one.

Is an EIN the same as a tax ID number?

An EIN is one type of tax ID number, specifically the federal employer identification number issued by the IRS. The term tax ID can also refer to a Social Security number, an Individual Taxpayer Identification Number (ITIN), or a state tax ID, so confirm which one is being requested.

Conclusion

Finding a business Employer Identification Number comes down to a simple order of operations: check your IRS confirmation letter and old tax returns first, look through bank and state paperwork second, and call the IRS Business and Specialty Tax Line at 1-800-829-4933 as the final step. Keep a copy of the confirmation letter somewhere safe once you have the number, and you will never need to hunt for it again. If you need someone else’s EIN, request a Form W-9 directly, it is the cleanest and most reliable way to get it.