- April 29, 2026
- Posted by:
- Category: EIN
How to Look Up an Existing EIN
What an EIN Is (and Why You May Need to Find It)
An Employer Identification Number (EIN) is a federal tax identification number assigned by the IRS to identify a business entity. You may need to locate an existing EIN to:
- Open or update a business bank account
- File federal or state tax returns
- Run payroll or issue Forms W-2/1099
- Complete vendor onboarding or customer credit applications
- Apply for business licenses and registrations
- Respond to IRS notices or verify your business identity
Before You Start: Know What “Looking Up” an EIN Means
There are two common scenarios:
- You are trying to find your own business’s EIN (you already have one, but don’t know where it is).
- You are trying to find another company’s EIN (for due diligence, vendor setup, or verification).
The steps differ because EINs are not generally searchable through a public IRS database for most private businesses.
How to Find Your Own EIN (Most Reliable Methods)
1) Check the IRS EIN Assignment Letter (CP 575) or Confirmation Notice (147C)
When an EIN is issued, the IRS provides an EIN Assignment Letter (often called CP 575). If you applied online, you may also have a confirmation page or PDF. Look for these in:
- Your business formation/starting-a-business folder
- Digital records (PDF downloads, scanned mail)
- Your accountant’s onboarding documents
2) Review Prior-Year Business Tax Returns and IRS Correspondence
Your EIN commonly appears on:
- Federal tax returns (for example, Forms 1120, 1120-S, 1065, 941, 940)
- IRS notices, letters, and payment vouchers
- Payroll tax filings and confirmations
3) Check Bank and Financing Documents
Banks and lenders often record the EIN on:
- Business account opening paperwork
- Loan applications and underwriting files
- Merchant processing agreements
4) Look in Payroll, HR, and Benefits Accounts
If you have employees, your EIN is frequently stored in:
- Payroll provider settings
- Quarterly payroll reports
- Benefits enrollment or workers’ compensation policy documentation
5) Check State Registration and Licensing Files
Many state tax registrations and business licenses request an EIN. If you’re reviewing state-level compliance, it may help to cross-reference your registrations and filings. For related tasks, see business registration requirements.
How to Request Your EIN from the IRS (If You Can’t Find It)
If you cannot locate your EIN, the IRS can provide it after verifying your identity and authority. The most common method is requesting an EIN verification letter (often referred to as a 147C letter).
Who Can Request EIN Confirmation
The IRS generally provides EIN confirmation to an authorized party, such as:
- The business owner (sole proprietor)
- A corporate officer
- A partner in a partnership
- A trustee (trust)
- An authorized representative with appropriate authorization on file
What to Have Ready Before You Contact the IRS
- Legal name of the business (exactly as registered)
- Any trade name/DBA used
- Business address on IRS records
- Name and title of the caller (authorized person)
- SSN/ITIN of the responsible party (as applicable)
How to Find Another Company’s EIN (What’s Possible and What’s Not)
There is no general public IRS EIN lookup tool for most private companies. However, you can often locate an EIN through legitimate business records depending on the organization type.
1) Public Filings for Certain Organizations
- Public companies: SEC filings may include tax identification details in certain contexts, though not always presented as an EIN field.
- Nonprofits: Many nonprofit records and public documents display an EIN.
2) Ask the Company Directly (Best for Vendor Onboarding)
If you need a vendor’s EIN for a W-9 or accounts payable setup, request a completed Form W-9. This is the standard and most accurate way to obtain the correct tax identification number for U.S. vendors.
3) Review Contracts, Invoices, and Prior W-9s
If you have an existing relationship with the business, their EIN may already appear in your records, such as:
- Executed contracts or master service agreements
- Prior-year W-9 forms
- Vendor onboarding packets
Common Reasons an EIN “Doesn’t Match” Your Records
- Using a SSN instead of an EIN: Common with sole proprietors who never applied for an EIN.
- Name mismatch: Legal name differs from DBA/trade name on documents.
- Entity changes: Converting from sole proprietor to LLC/corporation may require a new EIN depending on the situation.
- Typographical errors: Transposed digits or outdated forms.
- Multiple entities: Owners may have more than one EIN across different businesses.
Best Practices for Storing and Securing Your EIN
- Store the EIN Assignment Letter and 147C letter in a secure, centralized compliance folder.
- Limit EIN access to finance, payroll, and authorized administrators.
- Use a consistent legal name format across banking, payroll, and tax accounts.
- Track state registrations separately from the EIN to avoid confusion during renewals and filings.
FAQ: How to Look Up an Existing EIN
1) Can I look up my EIN online using an IRS search tool?
No general IRS public search tool exists for retrieving an EIN. For your own EIN, the fastest path is locating prior IRS documents or requesting EIN confirmation from the IRS after identity verification.
2) Where is my EIN most likely to be found if I already have one?
Common locations include the IRS EIN Assignment Letter (CP 575), prior-year federal tax returns, payroll filings (like Form 941), business bank account paperwork, and prior W-9 forms you completed for customers.
3) What if I applied for an EIN years ago and can’t find the confirmation letter?
You can request EIN confirmation from the IRS. Gather your business’s legal name, address on file, and caller authorization details so the IRS can verify the request.
4) Can my accountant or payroll provider request my EIN for me?
They may be able to help locate it in your records, but obtaining confirmation from the IRS typically requires the requestor to be an authorized party or properly authorized representative.
5) Is an EIN the same as a state tax ID number?
No. An EIN is issued by the IRS for federal identification. State tax IDs (such as sales and use tax accounts) are issued by state agencies. If you are managing state compliance, you may also need separate registrations, such as a West Virginia sales and use tax number depending on where you do business.
6) How do I find a vendor’s EIN for a W-9?
Request a completed Form W-9 from the vendor. This is the standard method to obtain the correct tax identification number and certification for U.S. vendor onboarding.
7) Can I use a company’s EIN to verify it is legitimate?
An EIN alone does not confirm legitimacy. Combine EIN information with business name verification, address confirmation, contract documentation, and (when applicable) state registration checks.
8) What if my business name changed—does my EIN change too?
A name change does not automatically require a new EIN, but your IRS records must reflect the updated legal name. If your entity type changed (for example, a new corporation formed), a new EIN may be required depending on the circumstances.
9) I found multiple EINs in my files—how do I know which one to use?
Match the EIN to the specific legal entity name on the document and confirm it aligns with the tax form you’re filing (for example, the EIN used for payroll filings may differ from another entity you own). When in doubt, verify against the EIN assignment letter or request IRS confirmation.
10) Does a single-member LLC always have an EIN?
No. A single-member LLC may use the owner’s SSN for certain federal tax purposes unless it has employees, elects corporate taxation, or otherwise needs an EIN for banking, payroll, or compliance reasons.