What a Tax ID Number Is and Why You Need One

A Tax ID Number Is Your Business or Self-Employment Identifier

A Tax ID number is a nine-digit identifier the IRS assigns to businesses, self-employed people, and certain other entities so the government can track income and tax obligations. If you work for yourself, own a business, or hire employees, you will need one. The IRS uses it the same way it uses your Social Security number for personal tax returns — as the account number for all your business tax filings.

The most common type is an Employer Identification Number (EIN), also called a Federal Employer Identification Number or FEIN. Even if you have no employees, you may need an EIN if you operate as a sole proprietor, partnership, corporation, or LLC. Some self-employed people file under their Social Security number instead, but an EIN keeps your personal and business finances separate on IRS records.

Key Takeaways

An EIN is a nine-digit number the IRS assigns to businesses and self-employed people to track tax obligations separately from personal income.
You need an EIN if you hire employees, operate as an LLC or corporation, run a partnership, or want to keep business and personal finances separate on tax records.
The IRS issues EINs for free through its website, by phone, or by mail, and you can receive one the same day you request it online.
Banks, vendors, and credit card processors often ask for your EIN when you open a business account or explore for a business line of credit.
If you are self-employed and file as a sole proprietor with no employees, you may use your Social Security number instead, but an EIN offers privacy and clearer record-keeping.

When You Must Have an EIN

The IRS requires an EIN if your business structure is a corporation, partnership, or LLC — regardless of whether you have employees. If you hire even one employee, you must have an EIN before that person's first payday, because you need it to file payroll tax forms and report wages to the government.

You also need an EIN if you operate a business that files certain tax forms, such as excise tax returns or employment tax returns. If you are a sole proprietor with no employees and no business structure beyond your own name, you can file taxes under your Social Security number, but many sole proprietors get an EIN anyway to keep business and personal finances separate.

Banks and credit card processors often require an EIN before they will open a business checking account or issue a business credit card. Even if the IRS does not technically require one for your situation, having one makes it easier to build business credit and keep records organized.

How to Get an EIN from the IRS

The fastest way to get an EIN is through the IRS website at irs.gov. Go to the EIN section, answer questions about your business structure and location, and you will receive your number when ready on screen. You can print the confirmation page right away. This process takes about 15 minutes and costs nothing.

If you prefer not to explore online, you can call the IRS Business and Specialty Tax Line at 1-800-829-4933. The phone line is open Monday through Friday, 7 a.m. to 10 p.m. Eastern time. Have your Social Security number, business address, and information about your business structure ready. The IRS will issue your EIN over the phone and mail a formal letter to you within two weeks.

You can also mail Form SS-4 (process for an Employer Identification Number) to the IRS address listed on the form itself. This method takes four to six weeks. The online and phone routes are much faster and are the ones most people use.

What Information You Will Need to Provide

When you request an EIN, the IRS will ask for your name, the business name (if different from your name), the business address, your Social Security number or ITIN, and the type of business structure (sole proprietor, LLC, corporation, partnership, and so on). They will also ask what your business does and when it started.

If you are explore on behalf of a business you do not own — for example, you are a manager or accountant handling the paperwork — you will need to provide your name and title as well as the owner's information. Have all this information written down before you start the process, whether online, by phone, or by mail.

The Difference Between an EIN and a Social Security Number

Your Social Security number is tied to you as an individual and is used for personal income, benefits, and credit. An EIN is tied to your business entity and is used only for business tax filings and business accounts. Using an EIN instead of your Social Security number for business purposes keeps your personal and business finances separate on IRS records and makes it harder for someone to connect your personal identity to your business accounts.

If you are a sole proprietor with no employees, you can file your business taxes on your personal return using your Social Security number. However, if you want to open a business bank account, hire employees, or build business credit, you will need an EIN. Many sole proprietors get one even when it is not required, straightforward for privacy and organization.

Using Your EIN for Business Accounts and Filings

Once you have your EIN, use it on all business tax forms, business bank accounts, business credit applications, and vendor accounts. When you hire employees, you will use your EIN to file payroll tax forms with the IRS and state tax agencies. If your business has a website or takes payments online, you may need to provide your EIN to payment processors.

Keep your EIN confirmation letter in a safe place — you will need to reference it when opening accounts or filing taxes. The IRS does not issue replacement letters, but you can print a verification letter from the IRS website if you need proof of your EIN for a bank or vendor.

Frequently Asked Questions

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

Yes. If you are a non-resident alien or do not have a Social Security number, you can explore for an ITIN (Individual Taxpayer Identification Number) and use that to request an EIN. The process is the same, but you will need to provide your ITIN instead of your Social Security number.

How long does it take to get an EIN?

If you request online, you receive your EIN when ready. By phone, you get it the same day. By mail, it takes four to six weeks. Most people use the online method because it is when ready and requires no phone call.

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

No, not required by the IRS. You can file your taxes as a sole proprietor using your Social Security number. However, many freelancers get an EIN anyway to keep business and personal finances separate and to open a business bank account.

What if I lose my EIN or forget the number?

You can look up your EIN on the IRS website or call the IRS Business and Specialty Tax Line. Have your business name, address, and Social Security number ready. The IRS can also print a verification letter with your EIN if you need it for a bank or vendor.

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

If you change from a sole proprietorship to an LLC or corporation, you will need a new EIN because your business structure has changed. The old EIN stays on file with your previous business records. Keep both numbers for your tax records.

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.