What a Federal Tax ID Number Is and Who Needs One
A Federal Tax ID Number, also called an Employer Identification Number (EIN), is a nine-digit identifier the IRS assigns to businesses, nonprofits, trusts, and certain individuals. The format is XX-XXXXXXX. You need one if you operate a business as anything other than a sole proprietor using your Social Security number, hire employees, run a nonprofit, or file certain tax forms.
The IRS issues EINs at no cost. You do not need a business license, bank account, or physical location to get one. The number itself is permanent — you keep the same EIN for the life of the business, even if you move, change the business structure, or change ownership.
If you are a sole proprietor with no employees and no separate business structure, you can use your Social Security number instead. But if you plan to hire anyone, form an LLC or corporation, or operate as a partnership, you will need an EIN before you can legally pay those people or file business taxes.
Key Takeaways
- You can get an EIN free from the IRS by applying online at IRS.gov, by phone, by mail, or by fax — online is fastest and gives you the number immediately.
- You need an EIN if you have employees, operate as a partnership or corporation, run a nonprofit, or file certain business tax forms.
- The IRS requires you to have an EIN before you hire your first employee, so apply before you bring anyone on payroll.
- Online applications are processed instantly during business hours; phone and mail applications take one to two weeks.
- You will need your Social Security number, the business start date, the business address, and the type of business structure (sole proprietor, LLC, S-corp, etc.).
How to Apply Online (Fastest Method)
The online application at IRS.gov/ein is the fastest way to get an EIN. You fill out Form SS-4 on the IRS website, submit it, and receive your number immediately if you apply during business hours (Monday through Friday, 7 a.m. to 10 p.m. Eastern time). The entire process takes about 15 minutes.
You will need your Social Security number, the date you plan to start or have started the business, your business address, the type of business structure (sole proprietor, partnership, S-corp, C-corp, LLC, nonprofit, trust, etc.), and a description of what the business does. Have these details ready before you start.
After you submit, the system confirms receipt and displays your EIN on screen. Write it down immediately. You can also print the confirmation page. The IRS will mail a formal letter with the EIN within two weeks, but you can use the number right away for hiring, opening a bank account, or filing taxes.
Applying by Phone or Mail if You Cannot Use Online
If you cannot access the online system, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933. Have the same information ready (Social Security number, business start date, address, structure type, and business description). A representative will ask you questions, assign the EIN over the phone, and mail you a confirmation letter. This takes one to two weeks for the letter to arrive, but you can use the number immediately after the call.
You can also mail Form SS-4 to the IRS. The address depends on your state; the IRS website lists the correct address for your location. Mail the form and wait one to two weeks for the IRS to process it and send your EIN by mail. This is the slowest method and should only be used if you have no internet access and cannot make a phone call.
Do not fax Form SS-4 unless you are applying for a nonprofit organization. The IRS fax line for nonprofits is listed on the form itself, but for-profit businesses should use online or phone.
What Information You Must Provide
The IRS requires specific information on Form SS-4, whether you apply online, by phone, or by mail. You will need your Social Security number (or ITIN if you are not a U.S. citizen), the legal name of the business exactly as it appears on your business documents, and the business start date — the date you began operations or plan to begin.
You also need the business address where the business is located or where you conduct business. A home address is acceptable. The IRS asks for the type of business structure — sole proprietor, partnership, LLC, S-corp, C-corp, nonprofit, trust, or estate. Finally, you provide a brief description of the business — for example, "consulting services," "retail clothing store," or "nonprofit food bank."
If you are applying on behalf of someone else (for example, as a business manager or accountant), you may need to provide your own name and contact information as well. The person whose Social Security number is on the application is considered the responsible party.
Timeline: When You Will Receive Your EIN
| Application Method | When You Get the Number | When You Get the Letter |
|---|---|---|
| Online at IRS.gov | Immediately (during business hours) | Within 2 weeks by mail |
| Phone: 1-800-829-4933 | During the call | Within 1–2 weeks by mail |
| Mail Form SS-4 | When IRS processes (1–2 weeks) | Within 1–2 weeks after processing |
You can use your EIN immediately for hiring employees, opening a business bank account, or filing taxes — you do not have to wait for the confirmation letter. However, keep the confirmation letter or the number you received online in a safe place. You will need it to reference your EIN with the IRS, your bank, and your accountant.
Special Situations: Nonprofits, Trusts, and Estates
Nonprofits follow the same process but must provide additional information: the nonprofit's legal name, the date it was formed, and its principal activity (for example, "food assistance" or "youth education"). Nonprofits can apply online, by phone, or by fax. The fax option is available only for nonprofits; the fax number is on Form SS-4 itself.
Trusts and estates also need EINs if they generate income or file a tax return. The responsible party is the trustee or executor. The process is the same — you provide the trust or estate name, the date it was created, and the type of trust or estate. Guardianships and conservatorships may also need EINs; check with a tax professional if you are uncertain.
If you are a foreign national without a Social Security number, you can use an Individual Taxpayer Identification Number (ITIN) instead. You must apply for an ITIN from the IRS before you can get an EIN. This adds extra steps and takes longer, so plan ahead if this applies to you.
What to Do After You Receive Your EIN
Once you have your EIN, keep it in a secure place — treat it like a Social Security number. You will need it to open a business bank account, hire employees, file business tax returns, and apply for business licenses or permits. Give it to your accountant or bookkeeper so they can file your taxes correctly.
If you hire employees, you must provide your EIN to them and to the IRS when you file payroll taxes. If you apply for a business loan or line of credit, lenders will ask for your EIN. If you operate multiple businesses, each one needs its own EIN — you cannot reuse the same number.
If you close the business, you do not need to "cancel" the EIN. Simply stop using it and do not file any more tax returns under that number. If you sell the business or it changes ownership, the new owner will need to apply for a new EIN; the old EIN stays with the previous owner.
Frequently Asked Questions
Can I get an EIN if I do not have a Social Security number?
You can use an Individual Taxpayer Identification Number (ITIN) instead of a Social Security number. You must apply for an ITIN from the IRS first, which takes several weeks. Once you have an ITIN, you can apply for an EIN using the same process. Contact the IRS or a tax professional for ITIN application instructions.
Do I need an EIN if I am a sole proprietor with no employees?
No. As a sole proprietor with no employees and no separate business structure, you can use your Social Security number on your tax return. However, if you plan to hire anyone in the future, you must get an EIN before you bring them on payroll.
How long does an EIN last?
An EIN is permanent. You keep the same number for the life of the business, even if you move, change the business structure, or change the business name. You only get a new EIN if you close the business and start a new one, or if the business is sold to a new owner.
What if I applied online but did not write down my EIN?
Check your email — the IRS sends a confirmation to the email address you provided. You can also call the IRS at 1-800-829-4933 with your Social Security number and business name, and they will provide the EIN. The formal letter with the EIN will arrive within two weeks.
Can I change my EIN after I receive it?
No. An EIN cannot be changed or reassigned. If you made an error on the application, contact the IRS to discuss your options. In most cases, the IRS will correct the record without issuing a new number. Do not apply for a second EIN for the same business.