What a Tax ID Number Is and Who Needs One

A Tax ID Number (also called an Employer Identification Number or EIN) is a nine-digit code the IRS uses to identify your business, nonprofit, or other entity for tax purposes. If you are self-employed, run a business with employees, or operate as a partnership or corporation, you will need one. The IRS assigns it to you at no cost.

You do not need a Tax ID if you are a sole proprietor with no employees and you use your Social Security Number for all tax filings. But if you hire anyone — even one person — or if you want to keep your personal and business finances separate, you should get one.

Key Takeaways

  • You can get a Tax ID Number free from the IRS online, by mail, by fax, or by phone, and you receive it immediately or within four weeks depending on the method you choose.
  • Online application through the IRS website (Form SS-4) is the fastest route and takes about 15 minutes; you get your number the same day.
  • You will need your Social Security Number, the legal name and address of your business, and the date you started or plan to start operating.
  • If you apply by mail or fax, processing takes two to four weeks, and you will receive your number by mail.

Applying Online for Immediate Results

The fastest way to get a Tax ID Number is through the IRS website using Form SS-4. Go to irs.gov, search for "Apply for an EIN," and follow the online application. The form takes about 15 minutes to complete. You will receive your nine-digit number on screen immediately after you submit, and you can print or save it right away.

To apply online, you need a Social Security Number or Individual Taxpayer Identification Number (ITIN), your business's legal name and address, and the date you started or will start your business. You will also answer questions about the type of business structure (sole proprietor, partnership, corporation, nonprofit, and so on). The IRS website walks you through each question.

Online application is available Monday through Friday, 7 a.m. to 10 p.m. Eastern Time. If you apply outside those hours, you can still submit the form, but you will not receive your number until the next business day.

Applying by Mail or Fax for Slower Processing

If you cannot apply online, you can mail or fax Form SS-4 to the IRS. Download the form from irs.gov or call 1-800-829-3676 to request it by mail. Fill it out by hand or type it, then mail it to the address listed on the form or fax it to the fax number provided (the number varies by state).

Processing by mail takes two to four weeks. Fax processing is slightly faster — usually one to two weeks — but both methods result in the IRS mailing your Tax ID Number to you. Keep a copy of your completed form for your records.

If you need your number urgently and cannot wait for mail or fax processing, phone application is an option. Call the IRS Business and Specialty Tax Line at 1-800-829-4933 during business hours. A representative will walk you through the form over the phone and assign your number verbally. You can then request written confirmation by mail.

What Information You Must Provide

Regardless of how you apply, the IRS will ask for the same core information. You need your Social Security Number or ITIN, the legal name of your business exactly as it appears on your business registration or formation documents, and your business address. If your business operates from home, use your home address.

You will also need to specify the date your business started or the date you plan to start. If you have not yet started, use the date you expect to begin operations. The IRS also asks what type of business structure you have — sole proprietor, partnership, S corporation, C corporation, nonprofit, trust, estate, or other. Answer honestly; the structure affects how you file taxes later.

If you have a business name that is different from your legal name (a "doing business as" or DBA), provide both. The IRS uses the legal name for the Tax ID but records the DBA so mail reaches you correctly.

Special Situations and Timing

If you are applying on behalf of a business you do not yet own — for example, you are a representative of a nonprofit or a new corporation — you will need to provide your name, title, and relationship to the business. The person applying does not have to be the owner, but they must have authority to represent the business.

If your business structure changes after you receive your Tax ID (for example, you convert from a sole proprietor to an LLC), you do not need a new number. The same Tax ID follows the business through most structural changes. However, if you sell the business or close it and start a new one, you will need a new Tax ID for the new entity.

If you applied and never received your number, or if you lost it, you can look it up. Call the IRS at 1-800-829-4933 with your Social Security Number and business name, and they will provide it over the phone. You can also request a copy by mail.

After You Receive Your Tax ID Number

Once you have your Tax ID, use it on all business tax forms, bank account applications, and official business documents. Your bank will ask for it when you open a business checking account. The IRS will use it to track your business tax filings — quarterly estimated taxes if you are self-employed, annual income tax returns, payroll taxes if you have employees, and any other tax obligations tied to your business.

Keep your Tax ID Number and the confirmation letter the IRS sends in a safe place. You will need to reference it for years. If you hire employees, you will use it to set up payroll and file employment tax returns. If you apply for business loans or credit, lenders will ask for it.

Frequently Asked Questions

Can I use my Social Security Number instead of getting a Tax ID?

If you are a sole proprietor with no employees, you can use your Social Security Number on your tax return. However, getting a Tax ID keeps your personal and business finances separate and is recommended if you plan to hire anyone or want privacy. A Tax ID is required if you have employees or operate as a partnership, corporation, or nonprofit.

How long does it take to get a Tax ID Number?

Online application gives you your number immediately — the same day. Phone application takes a few minutes, and you receive written confirmation by mail within two weeks. Mail and fax applications take two to four weeks for processing and delivery.

What if I made a mistake on my application?

If you made a minor error (misspelled name, wrong address), contact the IRS at 1-800-829-4933 and they can correct it. If the error is significant, you may need to apply for a new Tax ID. The IRS will advise you on the best course of action.

Do I need a Tax ID if I am a freelancer or independent contractor?

Not required, but recommended. You can use your Social Security Number on your tax return as a sole proprietor. However, a Tax ID keeps your personal information private when dealing with clients and vendors, and it is required if you hire subcontractors or employees.

Is there a cost to get a Tax ID Number?

No. The IRS issues Tax ID Numbers at no cost. Be cautious of websites or services that charge a fee to "help" you get one — they are unnecessary. You can apply directly to the IRS for free through irs.gov, by phone, mail, or fax.