Tax Identification Number (TIN)

What is a Tax Identification Number / TIN?

A tax or taxpayer identification number, also known as a TIN for short, is a number issued to individuals and organizations to track tax obligations and payments they make to the Internal Revenue Service (IRS). It is issued by the federal government. A TIN can be assigned by the Social Security Administration for individuals, or by the IRS for businesses and other organizations.

Types of Tax ID Numbers

A TIN is a generic term and refers to several different kinds of identifying numbers, which include:

  • A social security number issued to an individual
  • An Individual Taxpayer Identification Number (ITIN), issued to non-U.S. citizens currently residing, and often working, in the U.S.
  • An Employer Identification Number (EIN) issued to businesses and non-profit organizations
  • An Adoption Taxpayer Identification Number (ATIN), for children in the process of being adopted from outside the U.S.
  • A Preparer Taxpayer Identification Number, to identify accountants and firms involved with tax document preparation

Small businesses require a TIN, in the form of an Employer Identification Number, in order to issue payroll and make tax payments. To apply for an EIN, the IRS requires you to complete a Form SS-4.

A TIN is required on all tax documents, such as quarterly or estimated payments and annual filings.

State Tax ID Numbers

Some states also issue their own business identification numbers, in addition to the IRS identifier. Currently, those states are:

  • Massachusetts
  • New York
  • South Carolina

In those states, business need a state tax ID number and a federal tax ID number. Learn more about state TINs here.

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