This article outlines the definition of the federal Tax Identification Number (TIN) and the federal Employer Identification Number (EIN).

You may be wondering what exactly a federal TIN and a federal EIN is. We'll tell you.

federal TIN

A federal TIN is used by the IRS to track tax liabilities and payments.

  • If you're an employer, your TIN is your federal Employer Identification Number (EIN).
  • If you're not an employer, your TIN is your Social Security Number (SSN).

If you need a federal EIN

A federal EIN is a number assigned by the federal government employer to track payroll tax liabilities and payments.

All employers must have an EIN. A household employer cannot use their Social Security number, but they can use an EIN that was previously obtained as a sole proprietor. However, a sole proprietor can use their Social Security number as their EIN if the business has no employees. And is not required to file excise, employment, alcohol, tobacco, or firearms returns. A sole proprietorship is the only type of business that can use a Social Security number as its EIN.

Note A federal EIN is not the same as your Social Security Number.

What if I don't have a federal EIN?

The fastest and the best way to get one is to apply online at the IRS website where you will be given your EIN immediately.

Another way is to use Form SS-4. And wait several weeks. To receive an EIN over the phone, complete Form SS-4. And then call the IRS at 1.800.829.4933.

Tip We recommend that you enter your request online, because agencies are sometimes hard to reach by phone.