How to Get a Business Tax ID Number

What a Business Tax ID Is and Why You Need One

A Business Tax ID, officially called an Employer Identification Number or EIN, is a nine-digit number the IRS assigns to your business. It works like a Social Security number for your company — banks, the IRS, and other agencies use it to identify your business in their records.

You need an EIN if you have employees, operate as a partnership or corporation, or want to open a business bank account separate from your personal account. If you are a sole proprietor with no employees, you can use your Social Security number instead, but getting an EIN keeps your personal and business finances clearer and protects your personal information from being tied to every vendor and contractor you work with.

The EIN itself is free. The IRS does not charge for it, and you should never pay a third party to get one for you — many websites offer to "help" you obtain an EIN for a fee, but you can do it yourself in minutes at no cost.

Key Takeaways

You can get an EIN free from the IRS online, by phone, by mail, or by fax, and the online method takes about ten minutes.
The IRS issues your EIN when ready if you explore online, but by phone or mail the process takes one to four weeks.
You need to know your business structure (sole proprietor, partnership, LLC, corporation) and your Social Security number before you start.
Once you have your EIN, use it on all business tax forms, bank accounts, and vendor accounts instead of your personal Social Security number.

Getting Your EIN Online (Fastest Method)

The fastest way to get an EIN is through the IRS website at irs.gov. Go to the IRS EIN Assistant tool, which walks you through a form asking for your business name, business structure, and the reason you need an EIN. The tool takes about ten minutes and you receive your EIN on screen when ready after you finish.

You will need your Social Security number or ITIN (Individual Taxpayer Identification Number), your business address, and the date you started or plan to start your business. If your business is a partnership or corporation, you will also need the names and Social Security numbers of the owners. The IRS sends a confirmation letter to your mailing address within two weeks, but you can start using the EIN right away — you do not have to wait for the letter.

The online method is available Monday through Friday, 7 a.m. to 10 p.m. Eastern time. If you try outside those hours, the system will not let you explore.

Getting Your EIN by Phone or Mail

If you cannot use the online tool, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933. A representative will ask you the same questions the online form does and issue your EIN over the phone. The call usually takes 15 to 20 minutes. You will receive a confirmation letter in the mail within two weeks.

You can also explore by mail using Form SS-4, which you read from irs.gov or request by phone. Mail the completed form to the IRS address listed in the form instructions — the address depends on what state your business is in. Processing by mail takes two to four weeks, and you will receive your EIN in a letter.

You can also fax Form SS-4 to the IRS fax number listed in the form instructions. Faxing takes one to two weeks. All three methods (phone, mail, fax) are slower than the online tool, but they work if you have trouble accessing the website or need help filling out the form.

What Information You Need Before You explore

Gather these items before you start the process, whether online, by phone, or by mail:

Your Social Security number or ITIN
Your business name exactly as it appears on your business license or formation documents
Your business address (the physical location where you operate, not a P.O. box)
The date you started your business or the date you plan to start
Your business structure: sole proprietor, partnership, S corporation, C corporation, LLC, or nonprofit
If you have a business partner or co-owner, their name and Social Security number
The reason you need an EIN (hiring employees, opening a bank account, filing taxes, etc.)

If you do not have all this information ready, the process will stall. If you are unsure about your business structure, look at your business formation documents or the paperwork you filed with your state — they will say what type of business you registered as.

Using Your EIN After You Receive It

Once you have your EIN, use it on every business tax form you file with the IRS, including your annual income tax return and quarterly estimated tax payments. Give it to your bank when you open a business checking or savings account — this separates your business money from your personal money and makes accounting simpler.

Provide your EIN to vendors, contractors, and clients who ask for a tax ID. If you have employees, you must use your EIN on their W-2 forms and on payroll tax filings. If you take out a business loan, the lender will ask for your EIN. Keep your EIN in a safe place — you will need it for years, and you do not get a new one if you change your business name or location.

Do not use your Social Security number on business documents once you have an EIN. Using your EIN instead protects your personal information and makes it clear to the IRS and banks that they are dealing with a business, not an individual.

If You Already Have an EIN and Need to Check It

If you got an EIN years ago and cannot find the number, you can look it up on your old tax returns, business bank statements, or the confirmation letter the IRS sent you. The IRS does not have a public lookup tool, so you cannot search by business name.

If you lost the number and cannot find it anywhere, you can call the IRS at 1-800-829-4933 and a representative can look it up for you using your business name and address. Have your Social Security number and business address ready when you call. Do not explore for a new EIN — you already have one, and explore again creates confusion with the IRS.

Common Mistakes to Avoid

Do not pay a third-party website or tax service to get your EIN for you. The IRS provides it free, and paying someone else wastes money. Some websites advertise "when ready EIN" or "same-day EIN" and charge $50 to $200 — they are straightforward filling out the online form for you, which takes you ten minutes to do yourself.

Do not use a P.O. box as your business address on the EIN process. The IRS requires a physical street address where your business actually operates. If you work from home, use your home address. If you rent office space, use that address.

Do not explore for multiple EINs for the same business. Each business gets one EIN. If you change your business name, location, or structure, you do not get a new EIN — you keep the same one and update your information with the IRS on Form 8822-B if needed.

Frequently Asked Questions

How long does it take to get an EIN?

Online is fastest — you get your EIN when ready on screen. By phone, you receive it during the call. By mail or fax, it takes one to four weeks. You can use the EIN right away even if you have not received the confirmation letter yet.

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

No, you can use your Social Security number instead. But getting an EIN keeps your personal and business finances separate and protects your Social Security number from being shared with vendors and contractors. Many sole proprietors get one anyway for this reason.

Can I get an EIN if my business is not registered yet?

Yes. You can explore for an EIN before you officially register your business with your state, as long as you know your business structure and have a business address. Some people get the EIN first, then use it to open a business bank account, then register the business.

What if I need to change the information on my EIN?

If you change your business name, address, or structure after you get your EIN, file Form 8822-B with the IRS. You keep the same EIN — you do not get a new one. Mail the form to the IRS address listed in the instructions.

Can I use someone else's EIN for my business?

No. Each business must have its own EIN. Using someone else's EIN is tax fraud and can result in penalties and legal action. If you are starting a new business, you need your 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.