Taxpayer Identification Number (TIN) & EIN: Definition & Tax ID Number Help

You may need a tax ID number when you file your taxes or talk to the IRS. Here’s what tax IDs are & how to get one.

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When you file your tax return or need to talk to the IRS, you’ll likely have to provide a tax identification number, which is also called a TIN or tax ID number. Here’s what a tax ID number is and how to apply for one.

What is a tax ID number?

A tax identification number, or TIN, is a unique nine-digit number that identifies you to the IRS. It's required on your tax return and requested in other IRS interactions. Social Security numbers are the most popular tax ID numbers, but four other kinds are popular too: the ITIN, EIN, ATIN and PTIN.

Individual taxpayer identification number (ITIN)

What it is: An individual taxpayer identification number, or ITIN, is a nine-digit tax ID number for nonresident and resident aliens, their spouses and their dependents who cannot get a Social Security number. The IRS issues the ITIN.

How to get an ITIN: To get an ITIN, fill out IRS Form W-7. You must prove your foreign/alien status and identity. Also, you must supply a federal income tax return to your Form W-7 (there are some exceptions; the instructions to the W-7 have the details). Organizations called “acceptance agents” have IRS authorization to help people get ITINs.


  • You can’t claim the earned income tax credit if you’re using an ITIN to file your taxes.

  • ITINs always begin with the number 9.

  • Expirations: Any individual tax ID number not used on a tax return at least once for tax years 2018, 2019 or 2020 expired at the end of 2021. ITINs with middle digits containing 70 through 88, and 90 through 99 (if assigned before 2013), have also expired.

Employer identification number (EIN)

What it is: An employer identification number, or EIN, is a tax ID number for businesses that have employees; are corporations or partnerships; withhold taxes on income paid to nonresident aliens; have Keogh plans; are involved with certain types of organizations; or file employment, excise, or Alcohol, Tobacco and Firearms tax returns. The principal business must be in the United States or a U.S. territory, and the person applying for the EIN (it must be an individual, not an entity) must already have a Social Security number, ITIN or other EIN. The IRS may require an estate or trust to get an EIN.

How to get an EIN: You can apply for this tax ID number online with the IRS. You can also fill out IRS Form SS-4 and fax it or mail it to the IRS. International applicants can call 1-267-941-1099 to get an EIN.

Note: Your business may also need a separate state employer ID number.

Adoption taxpayer identification number (ATIN)

What it is: An adoption taxpayer identification number, or ATIN, is a temporary, nine-digit tax ID number the IRS gives to people who are in the process of adopting a child. The IRS provides the number if the adopting parents cannot get a Social Security number for the child in time to file their tax return. The number identifies the child, not the parent, and is needed for the parent to claim the child as a dependent.

How to get an ATIN: To get an ATIN, file IRS Form W-7A. You’ll need to attach a copy of the placement documentation. The child must be legally placed in your home for adoption. If you’re adopting a child from another country, you can still get an ATIN, but there are more rules (see the details here).


  • You cannot claim the earned income tax credit with this tax ID number (you can only use a Social Security number to do that).

  • It takes four to eight weeks to get an ATIN once the IRS gets your Form W-7A, so ask for it well before your tax return is due.

  • Unless you notify the IRS that the adoption is still pending, the IRS will automatically deactivate an ATIN after two years.

Preparer tax identification number (PTIN)

What it is: A PTIN is a preparer tax identification number. The IRS requires anyone who prepares or assists in preparing federal tax returns for compensation to have a PTIN. Tax preparers must put their PTIN numbers on clients’ tax returns.

How to get a PTIN: Preparers can get PTINs from the IRS online in about 15 minutes. Alternatively, they can fill out and mail IRS Form W-12. That method takes about four to six weeks.


  • Volunteer preparers don’t need PTINs.

  • You can look up the preparer on the IRS' PTIN directory.

  • Federal: $24.95 to $64.95. Free version available for simple returns only.

  • State: $29.95 to $44.95.

  • All filers get access to Xpert Assist for free until April 7.

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  • Federal: $39 to $119. Free version available for simple returns only.

  • State: $49 per state.

  • TurboTax Live packages offer review with a tax expert.

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  • Federal: $29.99 to $84.99. Free version available for simple returns only.

  • State: $36.99 per state.

  • Online Assist add-on gets you on-demand tax help.

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