What a Business Tax ID Is and Who Needs One
A Business Tax ID, officially called an Employer Identification Number or EIN, is a nine-digit number the IRS assigns to identify your business for tax purposes. The IRS uses it to track payroll taxes, income taxes, and other business filings. You need one if you have employees, operate as a partnership or corporation, or file certain business tax returns — even if your business has no income yet.
If you are a sole proprietor with no employees, you may be able to use your Social Security number instead. But most business structures — LLCs, S-corps, C-corps, partnerships, and nonprofits — must have an EIN before they can legally operate or hire staff.
Key Takeaways
- You can obtain an EIN free of charge directly from the IRS through their website, by phone, by mail, or by fax.
- The online application at IRS.gov takes about 15 minutes and gives you your number immediately upon approval.
- By phone, you speak to an IRS representative and receive your EIN the same day; the phone line is open Monday through Friday, 7 a.m. to 10 p.m. Eastern time.
- You will need your Social Security number or ITIN, your business structure type, and the business address to complete any application method.
- Paper applications by mail take four to six weeks, and fax applications take two to four weeks.
Applying Online Through the IRS Website
The fastest and most direct route is the IRS online EIN application at irs.gov. Go to the IRS website, search for "Apply for an EIN," and you will land on the Form SS-4 online tool. The form takes about 15 minutes to complete and you receive your EIN immediately after the IRS approves your application — usually within minutes.
You will need to provide your legal name, the business name (if different), your Social Security number or ITIN, the business address, the business structure type (sole proprietor, LLC, partnership, corporation, etc.), and a description of what the business does. The IRS will ask why you are requesting an EIN — common reasons are "starting a new business," "hiring employees," or "opening a bank account." Answer honestly; there is no wrong reason if you genuinely need one.
After you submit, the system tells you whether you were approved and displays your EIN on screen. Write it down or take a screenshot immediately. The IRS will also email you a confirmation, but the on-screen number is your proof of issuance.
Applying by Phone
If you prefer to speak with someone or have questions during the process, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933. The line is open Monday through Friday, 7 a.m. to 10 p.m. Eastern time. An IRS representative will walk you through the same questions as the online form and issue your EIN over the phone the same day.
Have your Social Security number, business name, business address, and business structure type ready before you call. The representative will read back your EIN at the end of the call. Ask them to repeat it and write it down carefully. They will also mail you a formal confirmation letter within two weeks, but the number you receive by phone is valid immediately.
Applying by Mail or Fax
You can also submit a paper Form SS-4 by mail or fax. Download the form from irs.gov, fill it out by hand or type it, and mail it to the IRS address listed on the form instructions — the address depends on your state. Processing takes four to six weeks by mail.
If you fax the form, send it to the fax number for your state, also listed in the Form SS-4 instructions. Fax processing takes two to four weeks. Keep a copy of what you sent and note the fax confirmation number or receipt date. You will not receive your EIN immediately; the IRS will mail it to you when they process the form.
Mail and fax are slower and carry more risk of error or lost documents. Use them only if you cannot access the internet or phone, or if you have a complex business situation that requires written explanation.
What Information You Must Provide
| Information Needed | What It Means | Where to Find It |
|---|---|---|
| Legal name | Your full name as it appears on your tax return or ID | Your driver's license or passport |
| Business name | The name you operate under; can be the same as your legal name or different | Your business plan or registration documents |
| Social Security number or ITIN | Your personal tax ID; required even if you are applying for a business EIN | Your Social Security card or tax return |
| Business address | The physical location where the business operates; a P.O. box does not count | Your lease, deed, or business registration |
| Business structure | Sole proprietor, LLC, partnership, S-corp, C-corp, nonprofit, trust, etc. | Your articles of organization or incorporation |
| Business description | What your business does in one or two sentences | Your business plan or industry knowledge |
After You Receive Your EIN
Once you have your EIN, use it on all business tax forms, bank account applications, and payroll documents. The IRS will use it to match your business filings and track your tax account. If you hire employees, you must provide your EIN to them for their W-4 forms.
Keep your EIN confirmation letter or email in a safe place. You may need to show it to a bank, a vendor, or a government agency. The EIN itself never expires, even if your business closes — the IRS keeps the number on file. If you start a new business later, you will need a separate EIN for that business.
Do not share your EIN publicly or with untrusted sources. Treat it like a business Social Security number. Scammers sometimes pose as the IRS and claim you need to "renew" or "reactivate" your EIN — this is false. The IRS will never call you unsolicited about your EIN.
Frequently Asked Questions
Do I need an EIN if I am a sole proprietor with no employees?
Not necessarily. Sole proprietors without employees can use their Social Security number on business tax returns. However, you may want an EIN anyway if you plan to hire staff later, open a business bank account, or apply for business credit. Getting one now saves you the step later.
How long does it take to get an EIN?
Online and by phone, you receive your EIN the same day — usually within minutes. By fax, two to four weeks. By mail, four to six weeks. If you need the number quickly, use the online or phone method.
Can I get an EIN if my business is not yet registered with the state?
Yes. You do not need state registration to obtain an EIN from the IRS. However, you may need to register your business with your state before you can legally operate or hire employees. Check your state's requirements separately.
What if I already have an EIN and need a second one for a different business?
Each business structure needs its own EIN. If you start a new business, even if you own both, you must obtain a separate EIN for the new business. Use the same application process.
Is there a cost to get an EIN?
No. The IRS issues EINs for free. If a website or service charges you to obtain an EIN, you are paying for convenience or help filling out the form — not for the EIN itself. You can always apply directly to the IRS at no cost.