Every business that files taxes, hires employees, or opens a business bank account needs an Employer Identification Number. The IRS assigns it when you first apply, sends you a confirmation notice, and that's often the last time most business owners think about it—until they need it for something and can't remember where it went.
The good news is that your EIN is documented in more places than you'd expect. Before you pick up the phone and navigate the IRS hold queue, work through the list below. One of these six sources will almost certainly have it.
If you're reading this because you genuinely lost your EIN and haven't been operating long, it's also worth knowing what the number looks like: nine digits formatted as XX-XXXXXXX. It's different from your Social Security number, which follows a different format (XXX-XX-XXXX). Keeping them straight matters, especially when filling out forms where both might be requested.
Where to Find Your EIN
1. Your Original IRS Confirmation Notice (CP-575)
When the IRS approves your EIN application, it sends a CP-575 notice—a one-page letter confirming your business name and assigned EIN. If you applied online, you can also download a confirmation letter immediately after approval.
This is the most reliable place to start. Check your email for the original confirmation if you applied online, or look through your business files for the physical letter. If you filed shortly after starting your business, it may also be with your original formation documents.
2. Prior Tax Returns
Any federal tax return your business has filed will have your EIN printed on it. For sole proprietors and single-member LLCs, look at Schedule C attached to your Form 1040. For partnerships, check Form 1065. For S-corps and C-corps, check Form 1120-S or Form 1120.
If you work with an accountant or bookkeeper, they'll have copies of your filed returns and can pull your EIN in minutes. This is often the fastest route.
3. Bank Records and Account Documents
If you opened a business bank account, your EIN was required during the application process. Check your account-opening paperwork or any correspondence from your bank. Many banks display the EIN associated with the account in online banking, or it appears on official account statements.
This is also a good reminder of why it's worth keeping a dedicated business bank account separate from personal finances—it creates a paper trail that includes your key business information, including your EIN. The 7 Reasons To Separate Business vs. Personal Bank Accounts covers this in more detail.
4. Old W-9 or 1099 Forms
If you've ever sent a W-9 to a client or received a 1099 for business income, your EIN (or Social Security number, if you used that instead) appears on those forms. Check your records for any contracts or vendor paperwork where you provided your tax ID.
Similarly, if you've issued 1099s to contractors you've paid, your EIN will appear in the "payer" section of those forms.
5. State Business Filings
Depending on how you structured your business, your EIN may appear in documents you filed with your state—particularly if you registered an LLC or corporation. Your articles of organization, annual reports, or state tax filings may include the number.
Your state's secretary of state website may also display EIN information in publicly searchable business records, though this varies by state.
6. Call the IRS Business & Specialty Tax Line
If none of the above works, the IRS can confirm your EIN over the phone. Call the Business & Specialty Tax Line at 1-800-829-4933, available Monday through Friday, 7 a.m. to 7 p.m. local time.
Be prepared to verify your identity as an authorized individual—the IRS will ask questions to confirm you're the business owner or an authorized representative before releasing the number. If someone else handles your business taxes (an accountant or enrolled agent), they can call on your behalf with the appropriate authorization in place.
How to Apply for an EIN If You Don't Have One
If you've gone through the list above and confirmed that your business doesn't have an EIN yet, applying is straightforward. The IRS online application takes about 15 minutes, and you'll receive your EIN immediately upon completion.
You'll need an EIN if you:
Have employees (or plan to hire)
Operate as a partnership, multi-member LLC, corporation, or S-corp
File certain excise taxes
Open a business bank account (most banks require it)
Work with clients who need to issue you a 1099
Sole proprietors with no employees can sometimes use their Social Security number instead, but using an EIN is cleaner and helps maintain the separation between personal and business finances.
What to Do Once You Have Your EIN
Once you've located or obtained your EIN, store it somewhere you'll reliably find it later. A password manager entry, a locked file in your document storage, or a secure note shared with your accountant are all reasonable options. The goal is avoiding this search the next time something needs it.
If you're looking up your EIN because you're ready to open a business banking account, Relay is worth a look—up to 20 checking accounts1 with no monthly fees and direct connections to QuickBooks Online and Xero make it an ideal choice for small businesses. Open a Relay account and you can be set up in minutes.
1Relay is a financial technology company and is not an FDIC-insured bank. Banking services are provided by Thread Bank, Member FDIC.
Frequently Asked Questions
What Is an EIN?
An Employer Identification Number (EIN) is a nine-digit tax ID assigned by the IRS to identify a business entity. It's formatted as XX-XXXXXXX and is required for filing business taxes, hiring employees, and opening a business bank account.
Can I Find My EIN Online?
Not through the IRS website directly—the IRS doesn't have an online EIN lookup tool. However, your EIN appears in documents you already have: prior tax returns, bank records, IRS confirmation notices, and state business filings. Some states also display EIN information in publicly searchable business records.
What If I Lost My CP-575 Confirmation Letter?
If you can't find your original CP-575 notice, you can request a replacement EIN confirmation letter (called a 147c letter) from the IRS. Call the Business & Specialty Tax Line at 1-800-829-4933 to request one by mail or fax.
Is My EIN the Same as My Social Security Number?
No. An EIN is a separate nine-digit number issued specifically to your business by the IRS. Some sole proprietors use their SSN in place of an EIN for certain purposes, but they are not the same number and serve different functions.
Can I Have More Than One EIN?
Generally no—each legal business entity has one EIN. However, if you operate multiple distinct businesses as separate legal entities (separate LLCs or corporations), each entity would have its own EIN.
What If My Business Has Changed Addresses Since I Got My EIN?
Your EIN stays with your business regardless of address changes. However, you should update your address with the IRS using Form 8822-B so that any IRS correspondence reaches you at the correct address.
