Getting a Business Tax ID Number: Step-by-Step

What a Business Tax ID Is and Who Needs One

A Business Tax ID, officially called an Employer Identification Number (EIN), is a nine-digit number the IRS assigns to identify your business for tax purposes. The IRS uses it to track your business income, payroll taxes, and other filings. If you operate as a sole proprietor with no employees and no business structure (like an LLC or corporation), you may be able to use your Social Security number instead — but most business owners need an EIN.

You need an EIN if your business is structured as a partnership, S-corporation, C-corporation, LLC, or nonprofit. You also need one if you have employees, even one part-time worker. Some sole proprietors without employees choose to get an EIN anyway to keep their personal and business finances separate on tax forms.

Key Takeaways

You can get an EIN for free directly from the IRS through their website, by phone, fax, or mail — no third-party service is required.
The online application at IRS.gov takes about 15 minutes and gives you your number immediately if you meet the requirements.
You need your Social Security number or Individual Taxpayer Identification Number, your business structure type, and your expected first payroll date or business start date.
If you apply by phone or mail, processing takes 4 weeks or longer, so online is faster if you are may be able to access.
Once you have an EIN, you use it on all tax forms, business bank accounts, and when hiring employees.

How to Get an EIN Online (Fastest Route)

The IRS online application at IRS.gov/ein is the fastest way to get an EIN. You fill out Form SS-4 on their website, answer questions about your business, and receive your number immediately. The whole process takes 10 to 15 minutes if you have the required information ready.

To apply online, you need your Social Security number or ITIN, your business structure type (sole proprietor, partnership, LLC, corporation, etc.), your business address, and the date you expect to start paying employees or the date your business began. You also need to know your principal business activity — the IRS provides a code list to choose from. The online system only works if you are applying as a U.S. citizen or resident alien with a valid Social Security number or ITIN.

After you submit, the IRS displays your EIN on the screen. Write it down or print the confirmation page immediately. The IRS will mail you an official EIN letter within two weeks, but you can start using the number right away for bank accounts and tax forms.

Applying by Phone, Fax, or Mail

If you cannot use the online system — for example, if you are a nonresident alien or your business structure does not fit the online form — you can apply by phone, fax, or mail. Call the IRS Business and Specialty Tax Line at 1-800-829-4933 during business hours. They will ask you the same questions as the online form and issue your EIN over the phone.

To apply by fax or mail, download Form SS-4 from IRS.gov, fill it out, and send it to the IRS fax number or address listed on the form. Processing by fax takes about 4 business days. Processing by mail takes 4 weeks or longer. You will receive your EIN by mail once the IRS processes your form.

Phone applications are faster than fax or mail but require you to call during business hours. The IRS phone line can be busy, especially during tax season, so plan to wait on hold.

What Documents and Information You Need

Before you start your application, gather these items:

Your Social Security number or Individual Taxpayer Identification Number (ITIN)
Your business name and address
Your business structure type (sole proprietor, partnership, LLC, S-corp, C-corp, nonprofit, etc.)
The date you expect to start paying employees, or the date your business began operating
Your principal business activity code (the IRS provides a searchable list on their website)
The name and Social Security number of the business owner or responsible party

If you are applying on behalf of someone else, you may need a power of attorney form. If your business is a partnership or corporation, have the names and Social Security numbers of all owners or officers ready. Nonprofits need their articles of incorporation or bylaws.

Timeline: When You Get Your EIN and When You Can Use It

The timeline depends on how you apply. Online applications give you your EIN immediately — you see it on the screen before you leave the IRS website. You can use it right away for opening a business bank account, hiring employees, or filing taxes. The official EIN letter arrives by mail within 2 weeks.

Phone applications also give you your number immediately during the call. Write down the number the representative provides and ask them to mail you a confirmation. Fax applications take about 4 business days, and mail applications take 4 weeks or longer. Until you receive your EIN, you cannot open a business bank account or file payroll taxes, so plan ahead if you are hiring employees soon.

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 income tax returns, payroll tax forms, and quarterly estimated tax payments. Provide it to your bank when you open a business checking or savings account. 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 for their W-4 forms. You also need it to register for state and local business licenses and tax accounts. Some vendors and suppliers may ask for your EIN when you set up a business account with them.

Keep your EIN letter in a safe place. You will need to reference it for years, and the IRS may ask you to provide it if there are questions about your business taxes.

Frequently Asked Questions

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

You need either a Social Security number or an Individual Taxpayer Identification Number (ITIN) to get an EIN. If you are a nonresident alien or do not have a Social Security number, you can apply for an ITIN from the IRS first, then use it to get an EIN. The online EIN application does not work for nonresident aliens, so you will need to apply by phone, fax, or mail.

Do I need to pay for an EIN?

No. The IRS issues EINs for free. You do not need to pay a third-party service to get one. Some websites charge fees to help you apply, but you can do it yourself at no cost through IRS.gov, by phone, or by mail.

What if I already have an EIN and need a second one for a different business?

You can have multiple EINs if you own multiple businesses with different structures or purposes. Each business gets its own EIN. Apply using the same process — online, by phone, fax, or mail — and provide the information for the new business. The IRS will issue a separate number.

How long does an EIN last?

An EIN does not expire. Once the IRS issues it, you keep it for the life of your business. If your business closes, you do not need to cancel the EIN — just stop using it and file a final tax return with the IRS.

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

If you change your business structure — for example, converting from a sole proprietorship to an LLC — you need a new EIN. The old one stays on record with the IRS, but your new structure gets a new number. Apply for a new EIN using the same process and provide your new business structure information.

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.