To find your LLC’s tax ID number, check your own records first: the IRS confirmation notice (CP 575), prior federal tax returns, your business bank account paperwork, any W-2s or 1099s your LLC has issued, and local business licenses. If none of those turn it up, call the IRS Business and Specialty Tax Line at 800-829-4933 and an agent can read the Employer Identification Number to an authorized member or manager after verifying identity.
Where Your EIN Already Appears
Most owners find the number within a few minutes of looking. The IRS itself recommends checking your own records before calling.1Internal Revenue Service. Employer Identification Number Start with these:
- The CP 575 notice. When the IRS first issued your EIN, it mailed this notice to the address on your application. It is the most authoritative document for your EIN and legal entity name. If you applied on paper, you may also have a copy of Form SS-4 with the assigned number written on it.
- Prior federal tax returns. Your EIN appears near the top of every return your LLC has filed. Multi-member LLCs taxed as partnerships show it on Form 1065; LLCs that elected S-corp treatment show it on Form 1120-S; single-member LLCs that obtained an EIN will find it on the Schedule C attached to the owner’s Form 1040.2Internal Revenue Service. About Form 1065, U.S. Return of Partnership Income
- Business bank records. Banks require an EIN to open a business account and keep it on file. Call your bank or check the account profile in online banking.
- W-2s and 1099s you’ve issued. If your LLC has employees, the EIN appears in Box b of every W-2. If you’ve paid contractors on Form 1099-NEC, it’s in the Payer’s TIN field.3Internal Revenue Service. Form 1099-NEC (Rev. April 2025)
- State and local business licenses or permits. Many municipal offices display the EIN on the permit itself.
Does Your Single-Member LLC Even Have an EIN?
If you’re the sole owner of an LLC with no employees and no excise tax obligations, one may never have been issued. The IRS treats single-member LLCs as disregarded entities by default, meaning you report business income on your personal return using your Social Security number.4Internal Revenue Service. Single Member Limited Liability Companies Plenty of single-member LLC owners apply for one voluntarily to open a bank account or satisfy state law, but if you never did, no amount of searching will turn one up. The IRS phone line can confirm whether an EIN exists for your entity.
Calling the IRS When Records Come Up Empty
The IRS Business and Specialty Tax Line at 800-829-4933 operates Monday through Friday, 7:00 a.m. to 7:00 p.m. in your local time zone, with Alaska and Hawaii following Pacific time.5Internal Revenue Service. Telephone Assistance Contacts for Business Customers Only an authorized person, meaning an officer, member, or manager of the LLC, can receive the EIN over the phone.1Internal Revenue Service. Employer Identification Number
Before you dial, have this in front of you:
- Your LLC’s exact legal name as it appears on the articles of organization filed with your state.
- The name and SSN or ITIN of the responsible party listed on the original EIN application.
- The business address currently on file with the IRS.
The agent will run through security questions, and if the answers match the record, they’ll read the EIN to you on the call. Expect about 10 to 15 minutes depending on hold times.
Getting a 147C Letter for Written Proof
Banks, lenders, licensing boards, and business partners often want documentation, not a number you scribbled down. While you have the IRS agent on the phone, ask for a 147C letter, formally titled “EIN Previously Assigned.” It’s the official replacement for a lost CP 575 and confirms both the EIN and the legal entity name on file. The IRS can send it by fax or by mail; fax is faster if you need it the same day. An entity transcript through the IRS is another way to confirm the EIN on record.1Internal Revenue Service. Employer Identification Number
Letting a CPA or Attorney Retrieve It
If you can’t make the call yourself, or your tax professional already handles IRS matters for the LLC, you can authorize them in writing. The IRS will not release your EIN to an unauthorized third party, so one of two forms needs to be on file first.
Form 2848, Power of Attorney, authorizes a representative such as a CPA, enrolled agent, or attorney to act on your behalf before the IRS, including inspecting and receiving confidential tax information. For an EIN request, the representative lists “EIN Application” as the matter and “Form SS-4” as the tax form.6Internal Revenue Service. Instructions for Form 2848
Form 8821, Tax Information Authorization, is narrower. It lets a designated person receive tax information but not represent you or advocate positions, and it must list the specific type of tax and the years involved. Writing “all years” will get it rejected.7Internal Revenue Service. Instructions for Form 8821
For most owners, Form 2848 is the more practical choice because it covers ongoing work, not just a single lookup.
Finding Another Company’s EIN
Looking up the tax ID for a business you don’t own is a different problem, because EINs are not public information by default. Your options depend on the entity.
Publicly Traded Companies
The SEC’s EDGAR database provides free access to filings from publicly traded companies.8U.S. Securities and Exchange Commission. Search Filings Annual reports on Form 10-K typically list the EIN on the cover page, and you can search by company name in EDGAR’s full-text search.9SEC.gov. EDGAR Full Text Search
Tax-Exempt Organizations
For nonprofits, the IRS Tax Exempt Organization Search lets you look up an organization by name or EIN.10Internal Revenue Service. Tax Exempt Organization Search Determination letters and publicly available Form 990 filings both contain the EIN.
Private Companies
For a private LLC, the direct route is to request Form W-9 from the business. W-9 is the standard form for collecting a taxpayer identification number in a business transaction, and any entity you’re paying or being paid by should furnish one. A payee who refuses to provide a correct TIN faces a $50 penalty for each failure.11Internal Revenue Service. Form W-9 (Rev. March 2024) Commercial credit databases like Dun & Bradstreet also compile business identification data, though access is paid.
Why Recovery Sometimes Fails: The Responsible Party Problem
The most common reason an owner can’t retrieve an EIN is that the responsible party on file with the IRS no longer matches who is calling. If the founding member left and a new manager took over without updating the record, the IRS still has the old name and SSN linked to the EIN. The new manager calls, can’t answer the security questions correctly, and the request stops there.
Form 8822-B is the fix, and it’s required within 60 days of any change in the responsible party’s identity.12Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business There’s no direct penalty for filing late, but if the IRS can’t reach the correct responsible party, you may never receive deficiency notices or demand letters while penalties and interest accrue in the background.13Internal Revenue Service. Form 8822-B, Change of Address or Responsible Party – Business Keep the form current and the right person can always call in and recover the number.