What Are Tax ID Numbers (TINs), EINs, ATINs, and PTINs?

A Taxpayer Identification Number (TIN) is used to track the income earned by a taxpayer. These records are then used to calculate tax payments and refunds. Taxpayer Identification Numbers may be used for other reasons, and are commonly used to identify you for credit application and reporting procedures. 

The IRS recognizes several types of Taxpayer Identification Numbers. Each is used in different circumstances. Most Americans will simply use their Social Security Number, but there are other numbers that certain taxpayers may need to know about. 

What are the Different Types of Taxpayer Identification Number?

If you read tax documents you will see a number of acronyms that involve identification numbers, including TIN, SSN, EIN, ATIN, ITIN, and PTIN. That can be confusing at first, but each one refers to a specific number with a specific purpose: 

What is a TIN?

TIN stands for Taxpayer Identification Number. It is a generic term used by the IRS to describe any number used to identify a taxpayer. All of the other numbers on this list are TINs. 

You will need a TIN of some kind to file a tax return or to accept legal employment anywhere in the United States. If a form asks for a TIN, fill in whatever type of number you are using.

All TINs are 9-digit numbers. Most TIN numbers are issued by the Internal Revenue Service (IRS). The exception is the Social Security Number (SSN), which is issued by the Social Security Administration. 

What is an SSN?

SSN stands for Social Security Number. The SSN is the most common TIN, and most American citizens will use their SSN as their TIN to track earnings, tax payments and benefits. An SSN may also be issued to a resident non-citizen. All dependents claimed on a tax return must be identified by an SSN, so most Americans receive one in early childhood.

A Social Security Number has nine digits in a specific format: XXX-XX-XXXX. It is issued by the Social Security Administration (SSA). If you need one for yourself or one of your children, you can apply for a Social Security Number here

What is an EIN?

EIN stands for Employer Identification Number. The IRS assigns an EIN to every employer. The EIN is usually used to identify the employer on reports of earnings and withheld taxes.

Any kind of business can apply for and receive an EIN, as long as it is located in the United States and the person making the application has a TIN. A business that changes its ownership structure may need to apply for a new EIN.

An EIN contains nine digits in the format XX-XXXXXXX. An EIN is issued by the IRS. The application process is free and you can apply for an EIN here

What is an ITIN?

ITIN stands for Individual Taxpayer Identification Number. The ITIN is issued by the IRS to individuals who need a TIN but are not eligible for an SSN due to residential status. The ITIN is usually used by non-resident aliens or other non-citizens that do not qualify for an SSN. An ITIN is used only for federal tax reporting.

An ITIN remains valid as long as it is used on tax returns. If an ITIN holder is not used on a tax return for five years it will expire. An ITIN number has nine digits and is formatted like an SSN: XXX-XX-XXXX. The first digit of an ITIN is always 9.

Most people who need an ITIN fall into these categories:

  • Non-resident aliens who need to file US tax returns.
  • Resident aliens who spend too much time residing outside the US to qualify for an SSN but need to file US tax returns.
  • Non-citizen dependents or spouses of US citizens or resident aliens.
  • Spouses or dependents of a non-resident alien who holds a valid visa.
  • A non-resident alien who is claiming any benefit under a tax treaty.
  • A non-resident alien researcher, professor, or student who needs to file a US tax return or claim an exception.

If you are in one of these categories, you can apply for an ITIN here

What is an ATIN?

ATIN stands for Adoption Taxpayer Identification Number. The IRS issues an ATIN to a child in a domestic adoption if the parents don’t have and can’t get the child’s SSN. The parents use the ATIN to identify the child as a dependent or claim a child care credit on their tax returns until the final adoption process is complete. When the adoption is complete the parents can apply for an SSN for the child. When the SSN is issued the ATIN will be deactivated. 

The ATIN will expire in two years even if no SSN is issued. You can apply for an extension if the adoption is not complete and the ATIN is nearing expiration. 

You and your adopted child must meet certain requirements for the child to be eligible for an ATIN:

  • The child must be your dependent according to the IRS definition of a dependent.
  • The adoption must be from an authorized placement agency and must comply with all legal requirements.
  • You must show that you tried to obtain the child’s SSN but could not.
  • The child must not be eligible for a new SSN. If the adoption is not yet final a new SSN cannot be issued and you should apply for an ATIN.
  • The adoption must be domestic, or if it is not the child must be a permanent resident alien or have certification of citizenship.

If you meet these requirements and you need a TIN for your adopted child you can fill out IRS form W-7A and mail or bring it to an IRS office.

What is a PTIN?

PTIN stands for Preparer Tax Identification Number. A PTIN is issued to anyone who is paid to prepare or help others prepare any US federal tax return, refund claim, or other tax documents. Each individual tax preparer must have their own PTIN. 

Anyone who prepares or assists in preparing tax documents for compensation needs a PTIN. You can apply for a PTIN here.

In Closing

A Taxpayer Identification Number is a central part of any American’s identity, and almost anyone living in or doing business in the US will need one, whether or not they are US citizens. Most Americans will only need a Social Security Number, but there are several specialized forms of Taxpayer Identification Number that are required for individuals in certain circumstances. It’s important to know what TIN you need and make sure you have it.

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