I Forgot My EIN What Do I Do Now

It’s a moment every business owner dreads—you’re filling out a crucial form, and your mind goes blank. "I forgot my EIN." That sinking feeling is real, but don't panic. More often than not, your Employer Identification Number is tucked away in documents you already have on hand.

The fastest places to look are usually your original EIN confirmation letter (CP 575), past tax filings, or even your business bank account statements.

Your Panic-Free Guide to Finding a Lost EIN

Misplacing your EIN can feel like losing the keys to your business, especially if you're a UK founder managing U.S. operations from across the pond. This nine-digit number, formatted as XX-XXXXXXX, is the lifeblood of your company's financial and legal identity in the States.

Without it, you hit a wall. You can't file federal taxes, open a U.S. bank account, hire employees, or apply for certain business licenses. The good news? Finding it is usually a straightforward process. You almost never need to start from scratch.

This guide will walk you through, step-by-step, the most common places your EIN is hiding. The goal here is to solve this in minutes, not days, by using the records you already possess.

The First Places to Check for Your EIN

Before you even think about spending time on hold with the IRS, let's do a quick search of your own files. The number is printed on dozens of official documents you've received or filed since your company was formed. Your first move should always be to check your internal records—it's the fastest way to get back on track.

Think back to when you first set up your company or opened that business bank account. Those initial setup files are a goldmine of information. We'll go through the most likely candidates, from formation paperwork to financial records, making sure you don't miss a thing. You can get a full refresher on what an EIN number is and why it's so important in our detailed article.

The flowchart below breaks down the two main paths for finding your EIN: first, checking your own documents, and second, contacting the IRS if all else fails.

As you can see, a quick check of your own records is the most efficient starting point. Save a call to the IRS as your last resort.

Before we dive into the specifics of each document, here’s a quick-reference table to guide your search.

Quick EIN Location Checklist

This table summarizes the most common places to find your existing EIN before you need to contact the IRS.

Document or Record Type	Where to Look	Pro Tip for UK Founders
EIN Confirmation Letter (CP 575)	This is the official notice from the IRS. Check your email or physical mail from when you applied.	This is your golden ticket. Many online formation services email this to you as a PDF. Search your inbox for "CP 575" or "EIN Confirmation."
Previous Federal Tax Returns	Look for Form 1120, 1065, or 941. The EIN is at the top of the first page.	If you used a U.S.-based accountant, they will have copies of all your filings on hand. A quick email to them can solve this in minutes.
Business Bank Account Records	Monthly statements or the original account opening documents often list the company's EIN.	Check the online portal for your U.S. bank. You can usually download PDF statements that will have the EIN printed in the account details section.
Business Licenses and Permits	Any state, county, or city licenses you've applied for will have your EIN on them.	This is less common for purely online businesses, but if you have a physical presence or specific regulatory needs, these documents are a great place to look.
Third-Party Payroll Provider	If you use a payroll service like Gusto or Rippling, your EIN is a core part of your account profile.	Log into your payroll provider's dashboard. Your EIN will be prominently displayed in your company settings or on any generated payroll reports (like Form 941).

Having this checklist handy can turn a stressful situation into a quick fix. Start with these sources, and you'll likely find your EIN without ever needing to pick up the phone.

Where to Find Your EIN in Business and Financial Records

If you've checked the obvious places and still can't find your EIN, don't panic. The next step is to methodically go through your company's official paperwork. Your EIN is like your business's financial fingerprint; it shows up on nearly every important legal or financial document your company has ever handled.

Think of it as a paper trail. You just need to know which documents to follow. The most reliable sources will always be your company formation records and past tax filings.

Scrutinize Your Formation Documents

Go back to the very beginning—when you first set up your LLC or C Corporation. While the initial documents filed with the state (like your Certificate of Incorporation in Delaware) won't have the EIN, the internal documents you created right after probably will.

Your best bets here are your company's core governance records. Look through your Operating Agreement (for an LLC) or your Corporate Bylaws (for a C Corp). It's common practice for founders or their attorneys to add the EIN to these documents once it's been assigned, creating a single source of truth for the company's vital stats.

Another excellent place to check is any paperwork from your bank. Remember setting up your business bank account? The welcome letters, account opening forms, or even old bank statements will almost certainly have your EIN printed on them. Banks are required by law to have it on file.

Pro Tip: Don't waste time scouring your state registration forms. The EIN is a federal number issued by the IRS after your company is legally formed at the state level. Focus on the documents you generated post-incorporation.

Review Past Tax and Financial Filings

This is probably the most foolproof method. Your federal tax returns are guaranteed to have your EIN, as it’s required for filing. It's usually printed right at the top of the first page.

Here are the specific forms to pull out:

• Form 1120 (U.S. Corporation Income Tax Return): Your EIN will be clearly marked in Box B.

• Form 1065 (U.S. Return of Partnership Income): Look for it in Box D.

• Form 941 (Employer's Quarterly Federal Tax Return): It’s right at the top of the form, you can't miss it.

Think beyond just tax returns, too. Have you ever applied for a business loan, a line of credit, or a payment processor account with a service like Stripe? Your EIN would have been a mandatory field on those applications.

And don’t forget your accounting software. If you use a platform like QuickBooks or Xero, your EIN is almost always saved in your company profile or business settings. It’s one of the first things you enter when setting up your account.

Calling the IRS to Get Your EIN

So, you've turned your office upside down, scoured your digital files, and still no EIN. It happens. When you've exhausted every other option, the next logical step is to go straight to the source: the IRS.

I know, the idea of calling the IRS probably doesn't spark joy, especially for founders based outside the US. But trust me, their Business & Specialty Tax Line is set up for exactly this kind of thing, and the process is surprisingly straightforward if you’re prepared.

What to Have Ready Before You Call

The whole game here is to make the call as quick and painless as possible. To do that, have all your business details in front of you before you dial. The IRS agent needs to confirm you're an authorized person—like a director or owner—before they can give out sensitive tax information.

Here’s a quick checklist of what you'll likely be asked for:

• Your full legal name and your role in the company

• The complete legal name of your business (e.g., "My Awesome Business LLC")

• The main business address the IRS has on file

• Your business structure (LLC, C Corp, etc.)

• Your Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN), if applicable

With this info handy, the agent can pull up your file, verify your identity, and give you the EIN right over the phone. We cover a few other recovery tactics in our guide on how to retrieve my EIN number, but calling is often the fastest way to get a definitive answer.

Pro Tip: From my experience, the best time to call is right when they open. Aim for between 7 a.m. and 9 a.m. Eastern Time. Wait times can get brutal later in the day, sometimes stretching over an hour. An early call can save you a massive headache.

IRS Phone Numbers for US and International Founders

The number you call depends on where you're located.

• Calling from the U.S. * Phone: 1-800-829-4933 * Hours: 7 a.m. to 7 p.m. local time, Monday to Friday.

• Calling from the UK (or any other country) * Phone: 1-267-941-1099 (Heads up: this is a paid call, not toll-free.) * Hours: 6 a.m. to 11 p.m. Eastern Time, Monday to Friday.

If you're calling from the UK, don't forget to factor in the time difference!

Taking a few minutes to make this call is far better than the alternative. You don't want to assume the EIN is lost forever and apply for a new one. That can open a whole new can of worms. For example, a UK founder who reapplies online might get rejected because of a tiny name mismatch—this is more common than you'd think. IRS data shows that roughly 18% of online EIN applications get kicked back, which can halt your business launch for 45-90 days while you sort it out.

A quick phone call confirms your existing number and keeps you from falling into that bureaucratic trap. With a little preparation, you can solve the missing EIN puzzle and get back to business.

What If a Third Party Got Your EIN for You?

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If you’re a UK founder who set up a US company, you probably didn’t go it alone. Most international entrepreneurs use a formation service or registered agent to navigate the paperwork of US incorporation and EIN applications. If that's you, finding your EIN could be a lot easier than you think.

Before you start digging through old files or bracing for a call to the IRS, take a moment. Think back to how you formed your company. Did you use a platform like Stripe Atlas, Doola, or Firstbase? Or maybe a specialized firm like ours at Set Up Stateside? These partners should be your first port of call.

Check With Your Formation Partner or Registered Agent

Good formation services and registered agents keep excellent records. It’s part of what you pay them for. Your EIN is a critical piece of that puzzle, and when they applied for it on your behalf, the IRS sent them the official confirmation—your CP 575 letter.

The first thing to do is log into the online dashboard your service provided. Look for a section labeled "Documents," "My Business," or "Company Filings." More often than not, you'll find a digital copy of your CP 575 letter sitting right there, ready to download.

Can't spot it in the portal? No problem. The next logical step is to get in touch with their support team.

Pro Tip: Be specific in your request. Instead of a generic "I lost my EIN," ask for "a copy of my CP 575 notice" or "the EIN confirmation letter." Using the official document name tells them exactly what you need and helps them find it much faster.

What to Have Ready Before You Call or Email

To make the process as smooth as possible, have a few key details handy before you reach out. This helps them confirm you are who you say you are and pull up your file right away.

You'll likely need:

• Your full business name (exactly as it was registered).

• The email address you used when you signed up.

• Your client or account ID number, if they gave you one.

Once they've verified your account, they can usually just email you the document within a few minutes or, at most, a few business hours. This is by far the fastest and least painful way to recover your EIN, saving you a phone call and a long wait on hold with the IRS.

How to Secure Your EIN After Recovery

You found it. Huge sigh of relief, right? But before you move on, take a moment to make sure you never have to go through that frantic search again. A few proactive steps right now will save you a world of trouble down the road.

Think of it this way: a simple “I forgot my EIN” moment can bring critical business operations to a halt, from opening a bank account to processing payroll. The best defense is creating a simple system with both digital and physical backups.

Build Your EIN Safety Net

Your first move should be creating a dedicated digital home for your most important company documents. I always recommend using a secure cloud service you already trust, like Google Drive or Dropbox, or even a password manager like LastPass.

Save a PDF of your EIN confirmation letter (the CP 575) in this folder. Be smart with the file name—something obvious and searchable like "Company Name - EIN Confirmation Letter" will make it easy to find in a pinch.

Next, go old-school. Print a hard copy of that confirmation letter and file it away with your other formation documents—think articles of incorporation or your operating agreement. This physical file is your lifeline if you ever get locked out of your digital accounts.

With your EIN now safely stored, circle back to any tasks that were stalled. Did a bank application get put on hold? Was a new payroll provider waiting on you? It's time to reach out and give them the number to get things moving again.

An incorrect or missing EIN is one of the top reasons for tax filing rejections. Forgetting your EIN isn't just a minor annoyance; it can cause real delays and compliance headaches that throw a wrench in your entire operation.

Requesting an Official EIN Verification Letter

What if you've lost the original CP 575 notice? Unfortunately, the IRS only issues that document once. The good news is you can get the next best thing: an EIN Verification Letter (147C).

This letter serves as an official replacement and is widely accepted by banks, state agencies, and other institutions that need formal proof of your EIN.

To get your 147C Letter, you'll have to call the IRS Business & Specialty Tax Line. After they verify you’re an authorized person for the company (like a director or owner), they can either mail or fax the letter to you. For international founders, especially in the UK, the fax option is almost always the quickest route.

We’ve put together a complete walkthrough here: Your Guide to Getting an EIN Verification Letter in the UK.

A mismatched or missing EIN is a surprisingly common problem. According to the CPA Journal, the average e-file rejection rate hovers around 6.5%, and a simple data entry mistake with an EIN is a frequent culprit. For a UK-based startup navigating US sales tax and payroll, that kind of delay can quickly spiral into a compliance nightmare.

Frequently Asked Questions About Lost EINs

Once you've tracked down your number, a few more questions usually pop up. Saying "I forgot my EIN" is often just the beginning—it can open up a whole new set of worries about what to do next or which IRS form is which.

This section tackles the most common follow-up questions we hear from UK founders. Let's clear up the confusion so you can get back to business.

I Can't Find My EIN. Can I Just Apply for a New One?

That’s a hard no. You should never apply for a new Employer Identification Number just because you’ve misplaced the one you already have for your business. An EIN is a bit like a Social Security Number for your company—it’s assigned for the life of the business entity.

Trying to get a second one for the same business will only create a messy paper trail and major headaches with the IRS. It can lead to:

• Tax filing nightmares: The IRS might see two separate entities, triggering penalties when they receive conflicting returns or notices for non-filing.

• Identity confusion: It complicates your company's entire compliance history, making it nearly impossible to track tax payments and payroll accurately.

• Banking roadblocks: Your bank account is tied to your original EIN. A new number won't match their records, which can cause serious issues with your accounts.

The only time you genuinely need a new EIN is if your business structure fundamentally changes—for example, a sole proprietorship becomes an LLC. If you've just lost the number, stick to the recovery steps.

How Long Does It Take to Get an Official EIN Confirmation Letter?

So you've lost that original letter and now you need official proof of your EIN. What you'll be requesting from the IRS is an EIN Verification Letter (147C). How quickly you get it in your hands really depends on one choice: fax or mail.

Once an IRS agent verifies your identity over the phone, you have two options:

1. Fax: This is by far the quickest route. The IRS can usually fax the 147C letter to you or your accountant within a few hours. At most, it takes a business day.

2. Mail: If you ask for it to be posted, get ready to wait. It can easily take 4 to 6 weeks to arrive, especially when you're waiting for it to cross the pond to a UK address.

For UK founders on a tight deadline—say, for a bank application or a critical vendor contract—fax is the only practical option. It’s a much faster and more reliable way to get the proof you need without putting your plans on hold for over a month.

What’s the Difference Between a CP 575 and a 147C Letter?

It's easy to mix these two up, but they play very different roles.

The CP 575 Notice is the original, one-time-only letter the IRS sends you right after your EIN is assigned. Think of it as your business’s tax birth certificate. The key thing to remember is that the IRS will never reissue it. Once it’s gone, it’s gone.

The 147C Letter, on the other hand, is an EIN Verification Letter. You can request this document any time you need to prove your EIN is valid. While it looks different from the CP 575, it has all the same crucial information: your official business name, address, and your EIN. Banks, government agencies, and partners all accept the 147C as official proof.

In short, if you've lost your CP 575, the 147C is its official, IRS-approved replacement.

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Navigating U.S. business formation and tax compliance from the UK can be complex, but you don't have to do it alone. Set Up Stateside offers end-to-end support, from EIN acquisition to ongoing bookkeeping and tax filing, ensuring you stay compliant and can focus on growth. Learn how we can become your dedicated U.S. accounting partner.