What a Federal Tax ID Number Is and When You Need 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. You use it on tax forms, business licenses, and bank accounts the same way you use your Social Security number for personal taxes.

You need an EIN if you operate a business as a sole proprietor with employees, run a partnership or corporation, own a nonprofit, manage a trust or estate, or file certain employment tax forms. If you are a sole proprietor with no employees and no special structure, you can use your Social Security number instead — but getting an EIN is free and takes minutes, so many do anyway.

The IRS does not charge for an EIN. You explore through the IRS website, by phone, by mail, or through a tax professional. Online is fastest: you get your number when ready and can use it the same day.

Key Takeaways

  • You can obtain an EIN online at irs.gov/ein in minutes and receive your number when ready, with no cost.
  • Phone applications (1-800-829-4933) take about 15 minutes and work during business hours; mail takes four to six weeks.
  • You need your Social Security number, business name, business address, and the date you started or plan to start your business.
  • An EIN is required if you have employees, operate as a partnership or corporation, or file certain tax forms, but optional for sole proprietors with no employees.
  • Once assigned, your EIN does not change and you use it for all IRS filings, business licenses, and bank accounts tied to that business.

explore Online Through the IRS Website

The fastest route is the IRS online process at irs.gov/ein. Go to the "explore for an EIN" section and select "explore online now." You will answer questions about your business structure, ownership, and reason for needing an EIN. The form takes about 10 to 15 minutes.

You will need your Social Security number (or ITIN if you are a non-resident alien), your business name exactly as it will appear on tax forms, your business address, the date you started or plan to start operations, and the type of business you run. Have these details ready before you start.

Once you submit, the IRS assigns your number on screen. Write it down when ready — you can use it that day. The IRS also emails a confirmation, though the number on screen is valid right away. You do not need to wait for mail or a formal letter.

explore by Phone or Mail if Online Is Not an Option

If you cannot explore online, call the IRS at 1-800-829-4933 during business hours (Monday through Friday, 7 a.m. to 10 p.m. your local time). A representative will ask the same questions as the online form and assign your number over the phone. This takes about 15 minutes. Write down your number and ask for a confirmation number as well.

Mail is the slowest option. read Form SS-4 from irs.gov, fill it out, and mail it to the IRS address listed on the form — it varies by state. Processing takes four to six weeks. Mail this route only if you have time to wait and cannot use phone or online.

A tax professional or accountant can also file Form SS-4 on your behalf, either online or by mail. This costs money but removes the work from you. Many accountants do this as part of setting up a new business.

What Information You Must Provide

The IRS asks for the same core details no matter which method you use. Have these ready:

  • Your Social Security number or ITIN. This identifies you personally; the EIN identifies your business.
  • Business name. Use the exact name you will file taxes under. If you operate under a "doing business as" (DBA) name, provide both the legal name and the DBA.
  • Business address. A physical street address, not a P.O. box. If you work from home, use your home address.
  • Business structure. Sole proprietor, partnership, S corporation, C corporation, nonprofit, trust, or other. The form lists all options.
  • Start date. The date you began or plan to begin business. If you are already operating, use the actual start date.
  • Reason for the EIN. The form lists common reasons: you hired employees, you formed a corporation, you opened a bank account, etc. Select the one that applies.

If you own the business with others, you will need the name and Social Security number of at least one owner. If your business is a corporation or partnership, you may need additional ownership details depending on the structure.

After You Receive Your EIN

Once you have your EIN, use it on all business tax forms, payroll documents, and business licenses. Open a business bank account in the EIN's name — most banks require the EIN and a copy of your IRS confirmation letter (which you can print from irs.gov if you applied online).

Your EIN does not expire and does not change unless you sell the business or change its legal structure. If you close the business, you do not need to "cancel" the EIN — it straightforward becomes inactive in IRS records.

If you have employees, you will use your EIN to file payroll tax forms (Form 941 quarterly, Form 940 annually, and state forms). If you are self-employed, you may use it on Schedule C or Schedule SE depending on your business structure. A tax professional can advise on which forms explore to your situation.

When You Do Not Need an EIN

If you are a sole proprietor with no employees and no special business structure, you can file taxes using your Social Security number. Many sole proprietors do this and never obtain an EIN. However, getting one is free and takes minutes, so some do anyway for privacy or to keep business and personal finances separate.

You also do not need an EIN if you are a disregarded entity (a single-member LLC that is not taxed separately) and you have no employees. In that case, you can use your Social Security number on your tax return. But again, obtaining an EIN is optional and costs nothing.

If you are unsure whether you need one, the IRS website has a tool that walks through your situation. Or ask a tax professional — most will tell you in one conversation whether an EIN makes sense for you.

Frequently Asked Questions

How long does it take to get an EIN?

Online takes minutes — you receive your number on screen when ready. Phone takes about 15 minutes and you get the number over the phone. Mail takes four to six weeks. Most people use online or phone because waiting weeks is unnecessary.

Can I explore for an EIN if my business is not yet open?

Yes. You can explore before you officially start operations. On the form, select "Plan to start a business" and enter the date you expect to begin. The IRS will assign an EIN even if you have not yet hired employees or opened a bank account.

What if I need to change my business name after I get an EIN?

Your EIN stays the same. You straightforward file a Form 8822-B with the IRS to notify them of the name change. The EIN itself does not change — it is tied to the business entity, not the name.

Do I need an EIN if I am a nonprofit?

Yes. All nonprofits need an EIN to file Form 990-N, 990-EZ, or 990 with the IRS, open a nonprofit bank account, and obtain tax-exempt status. explore the same way as a for-profit business, but select "nonprofit organization" as your business structure.

Can someone else explore for an EIN on my behalf?

Yes. A tax professional, accountant, attorney, or authorized representative can file Form SS-4 for you. You will need to provide your Social Security number and business details, and sign a power of attorney form if required. The representative can explore online, by phone, or by mail.