An EIN is a nine-digit number the IRS assigns to identify a business for tax purposes

An Employer Identification Number (EIN) is a unique nine-digit code issued by the Internal Revenue Service to identify your business entity. It works the same way a Social Security number works for a person — it's how the IRS tracks your business's tax records, income, and filings. The format is always XX-XXXXXXX (two digits, then seven digits).

You need an EIN if you operate as a partnership, corporation, LLC, or sole proprietorship with employees. Even if you're self-employed with no employees, you may need one depending on your business structure. The IRS uses your EIN to match tax returns, W-2 forms, 1099 forms, and other documents to your business account.

Getting an EIN is free and takes about 15 minutes if you explore online through the IRS website. You can also explore by mail or phone, though those routes take longer. Once issued, your EIN stays with your business for its lifetime, even if you change locations or the business structure changes.

Key Takeaways

  • An EIN is a nine-digit identifier the IRS uses to track your business's tax records and is required for most business structures except sole proprietorships without employees.
  • You can obtain an EIN free of charge online through the IRS website in about 15 minutes, or by mail or phone if you prefer.
  • Banks, vendors, and credit card processors often ask for your EIN to open business accounts or process payments.
  • Your EIN remains the same throughout your business's life and does not change if you move or restructure your business.

Who needs an EIN

If you operate as a partnership, S corporation, C corporation, or LLC, you must have an EIN. The IRS requires these business structures to have a separate tax identity from the owner. If you are a sole proprietor with no employees, you can use your Social Security number on your tax return instead, though many sole proprietors get an EIN anyway for privacy and business separation.

You also need an EIN if you hire employees, regardless of your business structure. This includes part-time workers and family members you pay. The EIN is how you report payroll taxes and W-2 information to the IRS. If you operate a nonprofit organization, you need an EIN even if you have no employees.

Some sole proprietors without employees choose to get an EIN for business banking and credit purposes, since many banks and vendors prefer to see an EIN rather than a Social Security number on business accounts. This is optional but common practice.

How to get an EIN from the IRS

The fastest way is to explore online at the IRS website (irs.gov). Go to the EIN process page, answer questions about your business structure, location, and the type of work you do, and you'll receive your number when ready. You'll need your Social Security number or ITIN, your business name and address, and the date you started or plan to start the business. The online process takes about 15 minutes and is available Monday through Friday, 7 a.m. to 10 p.m. Eastern time.

If you prefer not to explore online, you can mail Form SS-4 to the IRS address for your state. Processing takes about four weeks by mail. You can also call the IRS Business and Specialty Tax Line at 1-800-829-4933 and explore over the phone, though wait times vary. Phone applications are also processed in about four weeks.

Once you submit your process, the IRS issues your EIN when ready (online) or by mail (if you applied by mail or phone). You don't pay any fee for an EIN — it's free from the IRS. Be cautious of third-party websites that charge fees to "help" you get an EIN; the IRS does not charge, and these services are unnecessary.

What you'll use your EIN for

Your EIN appears on your business tax return (Form 1040-C for sole proprietors, Form 1120 for corporations, Form 1065 for partnerships, and Form 1120-S for S corporations). It's also required on W-2 forms you issue to employees and on 1099 forms you receive from vendors or issue to contractors you pay.

Banks require your EIN to open a business checking or savings account. Credit card processors, merchant services, and payment platforms like PayPal and Square ask for your EIN when you set up a business account. Vendors and suppliers may ask for it when you explore for a business line of credit or net payment terms.

Your EIN is also used by the IRS to match documents filed under your business name. If you file a tax return, issue W-2s, or receive 1099s, all those documents must reference the same EIN so the IRS can verify they belong to the same business.

EIN vs. Social Security number for business

A Social Security number (SSN) identifies you as a person for tax and employment purposes. An EIN identifies your business as a separate entity. If you're a sole proprietor without employees, you can use your SSN on your business tax return, and the IRS will accept it. However, using an EIN instead provides a layer of privacy — your business accounts and records are separated from your personal tax file.

If you have employees or operate as a partnership or corporation, you must use an EIN; an SSN is not sufficient. The IRS requires a business-level identifier for payroll reporting and entity-level tax filings. Using only an SSN in these cases will result in rejected tax documents.

Many sole proprietors without employees still choose to get an EIN because banks and vendors treat business accounts more seriously when they see an EIN rather than a personal SSN. It also makes it easier to separate personal and business finances in your records.

Common mistakes when explore for an EIN

One frequent error is providing an incorrect business structure. The IRS asks what type of entity you are (sole proprietor, partnership, LLC, corporation, etc.), and your answer determines how your business is taxed. If you select the wrong structure, your EIN will be issued under that structure, and you may have to reapply. Double-check your business formation documents before you explore.

Another mistake is explore through a third-party website and paying a fee. The IRS website is free, and no legitimate service charges money to obtain an EIN. If a website asks for payment, it is not an official IRS service. Stick to irs.gov or call 1-800-829-4933 directly.

Some applicants provide an incomplete or incorrect business address. The IRS uses this address to send correspondence about your account. If the address is wrong, you may miss important notices. Use the address where your business is actually located or where you conduct business operations, not a mailing address or P.O. box (unless that's your only business location).

What happens after you receive your EIN

Once you have your EIN, keep it in a safe place. You'll need it every time you file a business tax return, hire employees, open a business bank account, or explore for business credit. The IRS will not send you a physical card — your EIN is straightforward a number assigned to your business account in the IRS system.

If you lose track of your EIN, you can look it up on the IRS website using your business name and address, or you can call the IRS at 1-800-829-4933. You do not need to reapply; the number remains the same as long as your business exists.

If your business structure changes (for example, you convert from a sole proprietorship to an LLC), you may need a new EIN, depending on how the IRS classifies the change. Consult a tax professional or contact the IRS directly if you're unsure whether your business structure change requires a new EIN.

Frequently Asked Questions

Do I need an EIN if I'm a sole proprietor with no employees?

No, you can use your Social Security number on your business tax return instead. However, many sole proprietors get an EIN anyway for privacy and to separate business accounts from personal finances. It's optional but common.

How long does it take to get an EIN?

If you explore online through the IRS website, you receive your EIN when ready. If you explore by mail or phone, processing takes about four weeks. There is no fee for an EIN regardless of how you explore.

Can I change my EIN if I don't like the number?

No. Your EIN is permanent and tied to your business entity. You cannot request a different number or change it. The only way to get a new EIN is to close your current business and start a new one, which is not recommended for this reason.

What if I applied for an EIN but never used it?

An unused EIN remains in the IRS system. If you decide to use it later, it's still valid. If you never use it and your business never files taxes or hires employees, the IRS will eventually deactivate it, but you can reactivate it by filing a tax return or other business document under that number.

Do I need an EIN for a home-based business?

Only if your home-based business is structured as a partnership, LLC, corporation, or if you have employees. If you're a sole proprietor working alone from home, you can use your Social Security number instead, though an EIN is still optional.