How to Get a Federal Tax ID Number for Your Business

What a Federal Tax ID Number Is and Who Needs One

A Federal Tax ID Number, also called an Employer Identification Number or EIN, is a nine-digit identifier the IRS assigns to businesses, nonprofits, trusts, and certain other entities. It works like a Social Security number for your business — you use it on tax forms, bank accounts, and when hiring employees.

You need an EIN if you operate as a partnership, corporation, LLC, or nonprofit. If you are a sole proprietor with no employees, you can use your Social Security number on tax forms instead, though many sole proprietors get an EIN anyway to keep business and personal finances separate. The IRS does not charge for an EIN, and you can obtain one the same day you apply.

The IRS issues EINs through one channel: Form SS-4, Application for Employer Identification Number. You can submit it online, by phone, by fax, or by mail. Online is fastest — you receive your number immediately after the form is processed.

Key Takeaways

You can obtain an EIN online through the IRS website and receive your number the same day, with no fee.
Form SS-4 is the only document the IRS uses to issue an EIN, and you must complete it before applying through any method.
Online and phone applications are processed immediately; fax and mail applications take four weeks or longer.
You will need your Social Security number, business address, and information about your business structure and purpose to complete the form.
Once issued, an EIN does not expire and does not need to be renewed, even if your business closes or changes structure.

Applying Online for Immediate Issuance

The fastest route is the IRS online application at irs.gov/ein. The system is called the IRS EIN Assistant. You enter your information into a web form, and the IRS processes it in real time. If your application is complete and correct, you receive your nine-digit EIN on screen before you leave the site. You can print or save it immediately.

Online applications are open Monday through Friday, 7 a.m. to 10 p.m. Eastern time. The system is closed on federal holidays. You will need your Social Security number, the business owner's date of birth, a business address (a home address is acceptable), and basic information about what your business does and its structure — for example, whether it is an LLC, S corporation, or partnership.

If the system flags your application as incomplete or finds an error, it will tell you which field to correct before you submit again. Once you receive your EIN, write it down or save the confirmation page. You do not receive a physical certificate in the mail.

Applying by Phone or Fax

If you cannot use the online system, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933. Have Form SS-4 completed before you call. An IRS representative will ask you the questions on the form, verify your information, and issue your EIN over the phone. The call typically takes 10 to 15 minutes. Write down your number immediately and keep it in a safe place.

Phone lines are open Monday through Friday, 7 a.m. to 10 p.m. Eastern time, excluding federal holidays. Wait times are often long during tax season (January through April). If you fax Form SS-4 to the IRS, send it to 1-202-607-1734. The IRS will process your fax and mail your EIN to the address you provide on the form. Fax applications typically take two to four weeks.

Applying by Mail

You can mail a completed Form SS-4 to the IRS. The address depends on your state. The IRS website lists the correct mailing address for your location. Mail your form to the address listed for your state, and include a cover letter with your name, phone number, and email address so the IRS can contact you if there are questions.

Processing time for mailed applications is typically four weeks, though it can take longer during busy periods. The IRS will mail your EIN to the address you provide on the form. If you need your EIN sooner, use the online or phone method instead.

Information You Will Need to Provide

Before you start your application, gather these documents and details:

Your Social Security number and date of birth
The business owner's name and address (home address is acceptable)
The business name and address (can be the same as the owner's address)
A description of what the business does
The business structure: sole proprietorship, partnership, LLC, S corporation, C corporation, nonprofit, trust, or other entity type
The date the business began or will begin operations
The number of employees you have or expect to have
Your state tax ID number, if you have one

You do not need to have a business license, lease, or bank account open before you apply for an EIN. The IRS issues the number based on the information you provide on Form SS-4.

What Happens After You Receive Your EIN

Once you have your EIN, use it on all business tax forms, including your annual income tax return, payroll tax forms, and sales tax returns (if your state requires them). You will also use it when opening a business bank account, hiring employees, and applying for business loans or licenses.

An EIN does not expire. You keep the same number for the life of your business, even if you change the business structure, move to a different state, or change the business name. If your business closes, you do not need to notify the IRS or cancel the EIN — it simply becomes inactive.

If you lose your EIN or cannot find it, you can look it up on the IRS website or call the Business and Specialty Tax Line at 1-800-829-4933. Have your Social Security number and business information ready.

Common Reasons Applications Are Delayed or Rejected

The most common reason for delay is incomplete information on Form SS-4. If you leave fields blank or provide conflicting information — for example, listing different business addresses in different parts of the form — the IRS will contact you to clarify. Providing a phone number and email on your application speeds up this process.

Applications are sometimes rejected if the IRS suspects fraud or if the information does not match IRS records. For example, if you provide a Social Security number that does not match your name in the Social Security Administration database, the IRS will flag it. If this happens, the IRS will contact you. Respond promptly with corrected information or documentation that explains the discrepancy.

If you apply online and receive an error message, the system will explain what went wrong. Common errors include typos in your Social Security number, a date of birth that does not match IRS records, or a business address that the system cannot verify. Correct the information and resubmit.

Frequently Asked Questions

Can I apply for an EIN if I do not have a Social Security number?

No. The IRS requires a valid Social Security number or Individual Taxpayer Identification Number (ITIN) to issue an EIN. If you are a noncitizen without an SSN or ITIN, you must obtain an ITIN from the IRS before you can apply for an EIN. This process takes several weeks and requires Form W-7.

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

No, but many sole proprietors get one anyway. You can use your Social Security number on tax forms instead. An EIN is required only if you have employees, operate as a partnership or corporation, or run a nonprofit. Getting an EIN as a sole proprietor is optional and free, and it keeps your business and personal finances separate.

How long does it take to get an EIN?

Online applications are processed immediately and you receive your number on screen. Phone applications take 10 to 15 minutes and you receive the number during the call. Fax applications take two to four weeks. Mail applications take four weeks or longer. If you need your EIN quickly, use the online or phone method.

What if I applied online but did not save my EIN?

Call the IRS Business and Specialty Tax Line at 1-800-829-4933 with your Social Security number and business information. An IRS representative can look up your EIN and provide it over the phone. Have your business address and the date you applied ready.

Can I change my EIN if I change my business structure?

No. Your EIN stays the same even if you change from a sole proprietorship to an LLC, or from an LLC to a corporation. You do not need to apply for a new one. However, if you sell your business to someone else, the new owner must apply for their own EIN.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.