Tax ID number, Employer ID number, and ITIN? What's the Difference?

Tax ID, Employer ID, or Individual Tax ID Number Explained

Three general types of taxpayer ID numbers: Social security is the most common identifier for tax purposes, Dept of treasury is for people who aren't eligible for the other taxpayer ID numbers, you EIN is a federal tax identification number for businesses.

Image by Adrian Mangel © The Balance 2019

You're filling out a form and you are asked for your personal or business "tax identification number." There are actually several different numbers that can be used for tax identification purposes and you will need to know the difference between these tax ID numbers so you can give the correct one. 

As a business owner, you need to know the different kinds of identification that can be accepted for different business purposes. 

What is the Difference Between a Tax ID, Employer ID, and an ITIN?

A Taxpayer Identification Number is a generic term used by the Internal Revenue Service to designate the types of numbers which it allows to be used for tax and identification purposes.

Tax ID numbers are primarily used to track payments to individuals for federal income tax and other tax purposes, but they have also become used for a variety of identification purposes.

The three general types of taxpayer ID numbers are

  • Social Security Number (SSN)
  • Individual Taxpayer ID Number (ITIN), and
  • Employer ID Number (EIN).

The IRS also has two other special taxpayer ID numbers: the ATIN for pending adoptions and the PTIN for tax preparers.

Social Security Number

A social security number (SSN) is the most common identifier for personal identification and tax purposes. SSN's are used by employers to report the annual income of employees for their income tax returns. It's used to determine Social Security and Medicare eligibility and benefit payments. The SSN is also used to identify workers for work eligibility through the U.S. Customs and Immigration system.

Other times a Social Security Number might be requested:

  • To open a bank account
  • To apply for a passport
  • On a federal student loan application
  • To apply for Medicare and Social Security benefits
  • To apply for public assistance, including unemployment benefits
  • To check credit

if someone isn't eligible for a Social Security number, they may be able to apply for and receive an Individual Taxpayer ID Number (ITIN).

Individual Taxpayer ID Number (ITIN)

An ITIN is for people who aren't eligible to receive a Social Security Number or Employer ID Number. An employer can accept an ITIN from an individual for tax purposes (for filling out a W-4 form at hire, for example).

The IRS issues ITINs to people who need a tax identification number to process tax returns and payments.

Who might need an ITIN:

  • Non-resident alien filing a U.S. tax return and not eligible for an SSN
  • U.S. resident alien (based on days present in the United States) filing a U.S. tax return and not eligible for an SSN
  • Dependent or spouse of a U.S. citizen/resident alien
  • Dependent or spouse of a non-resident alien visa holder.

ITIN's are for tax reporting purposes only; the number cannot be used for identification purposes. The IRS emphasizes that the ITIN is NOT used:

  • To authorize someone to work in the U.S.
  • To make someone eligible for Social Security benefits, or
  • To qualify a dependent for an Earned Income Tax Credit.

Employer ID Numbers: Who Needs Them

Employer ID number (EIN) An Employer ID (or EIN, for short) is a federal tax identification number for businesses. Although it's labeled as an identifier for "employers," you don't have to have employees to need an EIN.

In addition to being used for paying business income taxes, an Employer ID is used for other situations:

Read more about when your business might need an EIN.

Business Types and Tax ID Numbers

sole proprietorship commonly uses the owner's Social Security number for the tax number for the business. Since the business files and pays taxes through the owner's personal tax return, the SSN is the only Taxpayer ID Number needed.

Businesses that are registered with the IRS typically use an Employer ID number for business identity. An Employer ID number (EIN) is used by all other types of businesses, even if the business has no employees. Banks often require a new business to have an EIN before they can open a business bank account.

The single-member LLC business type is an exception. If you are the sole owner of an LLC, you should use your Social Security Number, not the tax ID number (EIN) of the business. 

How to Get a Tax ID Number

To get a Social Security Number, use this Social Security Administration web page on Social Security Numbers and Cards.

You can apply for an Individual Taxpayer ID Number (ITIN) by completing IRS Form W-7 and mailing it to the IRS, or you can apply in person.

To apply for an Employer Id Number (EIN), use one of these four easy application methods, including an online application.

Does My Business Need a State Tax ID Number? 

If you do business in a state, including having income, hiring employees or selling goods or services, you will also need to get a state tax identification number for other state identification purposes, like sales taxes. This number is issued when you register with your state department of revenue.

Another Type of Tax ID Number: The Credit Privacy Number

A credit privacy number (CPN) is used in place of a Social Security Number, in some cases, to keep transactions more private. There are pros and cons to using a CPN. They are often marketed as helping you improve your credit rating, but that's not true. They may have some benefit in specific situations. Read more about these benefits and drawbacks to the CPN.