EIN (employer identification number)
Learn what an EIN is, who needs one, and how to apply for free through the IRS.
Published Thursday 23 July 2026
Table of contents
Key takeaways
- An Employer Identification Number (EIN) is a free, nine-digit number the IRS assigns to your business for tax purposes. You can apply online and receive it immediately.
- Any business with employees, a partnership, a corporation, or a multi-member LLC is required to have an EIN. Sole proprietors and single-member LLCs benefit from getting one too.
- Your EIN keeps your personal Social Security Number off business documents, which helps protect your identity. It's also required to open a business bank account, hire employees, and file certain tax returns.
- Once you have your EIN, connect it to a business bank account and accounting software to keep your finances organized from day one.
What is an employer identification number (EIN)?
An Employer Identification Number (EIN) is a unique nine-digit number the IRS assigns to your business. It identifies your business for federal tax purposes, similar to how a Social Security Number identifies you personally.
You might also hear it called a federal tax identification number or federal employer identification number. The format looks like this: XX-XXXXXXX. Regardless of the name, it's the same number.
Your EIN is essential for several core business activities. You'll need it to open a business bank account, hire employees, apply for business financing, and file federal tax returns.
Who needs an EIN?
Not every business is legally required to have an EIN, but most businesses benefit from getting one.
The IRS requires an EIN if your business meets any of these criteria:
- Has employees. Any business that pays wages must have an EIN for payroll tax reporting.
- Operates as a corporation or partnership. These structures require an EIN regardless of whether they have employees.
- Is a multi-member LLC. LLCs with more than one member must apply for an EIN.
- Files certain tax returns. Excise, alcohol, tobacco, firearms, or employment tax returns all require an EIN.
Even if you're not required to get one, it's still a good idea. Sole proprietors and single-member LLCs should seriously consider applying.
Without an EIN, you'd use your personal Social Security Number on tax forms, invoices, and vendor paperwork. That puts your personal information at risk. A GAO report (GAO-24-105281) also found $80 billion in unpaid taxes tied to sole proprietors underreporting income each year, making proper tax identification more important than ever.
How to apply for an EIN
Applying for an EIN is free. You should never pay a third-party service for something you can do yourself at no cost. The IRS offers three ways to apply.
- Online (recommended). Visit the IRS EIN Assistant during business hours (7 am to 10 pm Eastern, Monday through Friday). You'll receive your EIN immediately after completing the application. The IRS limits online applications to one per responsible party per day.
- By fax. Complete Form SS-4 and fax it to the IRS. You'll typically receive your EIN within four business days.
- By mail. Complete Form SS-4 and mail it to the IRS. Processing takes approximately four weeks.
What you need for your EIN application
Before you start your application, gather a few key details. Having this information ready makes the process faster.
- Business structure type. Know whether you're registering as a sole proprietorship, LLC, partnership, corporation, or another entity type.
- Responsible party information. This is the owner or an authorized person who controls the business. You'll need their full legal name and Social Security Number (or Individual Taxpayer Identification Number).
- Application reason. The IRS asks why you're applying, for example, starting a new business, hiring employees, or opening a bank account.
- US presence. Your business must be located in the United States or US territories to apply.
The responsible party's information is permanently linked to the EIN. Choose this person carefully, because changing it later requires contacting the IRS directly.
EIN vs. Social Security Number
An EIN and a Social Security Number (SSN) are both tax identification numbers, but they serve very different purposes. Understanding the difference helps you use the right one.
An EIN uses the format XX-XXXXXXX and identifies your business. An SSN uses the format XXX-XX-XXXX and identifies you as an individual. The IRS uses each number to track different types of tax obligations.
Use your EIN for all business-related activities: tax filings, payroll, vendor forms, and bank accounts. Use your SSN for personal tax returns and personal financial matters.
One of the biggest advantages of having an EIN is identity protection. When you use your EIN instead of your SSN on business documents, you reduce the risk of personal identity theft. Your SSN stays private, and your business operates under its own number.
EIN vs. tax identification number (TIN)
A tax identification number (TIN) is a broad term the IRS uses for any number that identifies a taxpayer. An EIN is one specific type of TIN.
Other types of TINs include:
- Social Security Number (SSN). Issued to individuals for personal tax purposes.
- Individual Taxpayer Identification Number (ITIN). Issued to individuals who need a US tax number but don't qualify for an SSN.
- Adoption Taxpayer Identification Number (ATIN). A temporary number for children in the adoption process.
- Preparer Tax Identification Number (PTIN). Required for paid tax return preparers.
A federal EIN and a state tax ID are different numbers. Your EIN is issued by the IRS for federal purposes. Many states issue their own separate tax identification numbers for state-level obligations like sales tax or state payroll tax. You may need both.
When do you need a new EIN?
Your EIN doesn't last forever in every situation. Certain business changes require you to apply for a new one.
You'll need a new EIN if you:
- Change your business structure. For example, converting from a sole proprietorship to an LLC, or from a partnership to a corporation.
- Receive a new charter. If your business is granted a new corporate charter by the state, you'll need a new EIN.
- Create a subsidiary or merge. New subsidiaries and merged entities each need their own EIN.
However, not all changes trigger a new EIN. Simply changing your business name, your address, or adding a new location does not require a new number. You can update that information with the IRS while keeping your existing EIN.
Benefits of having an EIN
Getting an EIN gives your business a stronger foundation. Even if you're not legally required to have one, the benefits make it worthwhile.
- Separate business and personal finances. An EIN lets you open a business bank account in your company's name, which keeps your personal and business transactions apart.
- Protect your identity. Using an EIN instead of your SSN on invoices, W-9 forms, and vendor agreements reduces your exposure to identity theft.
- Build business credit. Lenders and credit agencies use your EIN to track your business's credit history. A strong business credit profile can help you access better financing.
- Hire employees. You can't run payroll without an EIN. It's required for reporting employment taxes to the IRS.
- File taxes properly. Certain tax returns, including partnership and corporate returns, require an EIN.
Manage your business finances with Xero
Once you have your EIN, you're ready to set up the financial foundation of your business. With your EIN, you can access the essential services your business needs to operate.
The IRS recommends waiting up to two weeks before e-filing with a newly issued EIN. The IRS systems need time to register your number in their database.
While you wait, you can start planning your next steps. Open a dedicated business bank account using your EIN. Set up accounting software to track income and expenses from the start.
Begin building your business credit history by using your EIN for credit applications. Organize your records so you're ready when tax season arrives.
Xero's accounting software connects to your bank, automates reconciliation, and keeps your finances organized in one place. You can track expenses, send invoices, and access real-time reports from anywhere. To see how it works for your business, get one month free.
FAQs on EINs
These are common questions about EINs.
How do I find my EIN?
Check the confirmation notice the IRS sent when you first applied. You can also find your EIN on previously filed tax returns, old bank account applications, or any correspondence from the IRS. If you still can't locate it, call the IRS Business and Specialty Tax Line at 800-829-4933.
Do I need an EIN for my LLC?
Multi-member LLCs are required to have an EIN. Single-member LLCs without employees aren't legally required to get one, but it's recommended. An EIN protects your SSN, simplifies business banking, and helps you build credit and apply for business licenses in your company's name.
Can I use the same EIN for multiple businesses?
It depends on your business structure. A sole proprietor can use one EIN across multiple businesses since they all operate under the same legal entity. However, if each business is a separate legal entity, like a separate LLC or corporation, each one needs its own EIN.
How long does it take to get an EIN?
If you apply online, you'll receive your EIN immediately. Fax applications take approximately four business days. Mail applications can take up to four weeks. The online method is the fastest and most convenient option.
Does an EIN expire?
No. Once the IRS assigns an EIN to your business, it stays active permanently. Even if you close your business, the IRS never reassigns that number to another entity. You may need to close the associated tax account, but the EIN itself does not expire.
Related terms
Learn more about EINs
Disclaimer
This glossary is for small business owners. The definitions are written with their requirements in mind. More detailed definitions can be found in accounting textbooks or from an accounting professional. Xero does not provide accounting, tax, business or legal advice.