What Is a Tax Identification Number (TIN)?

Julia Kagan is a financial/consumer journalist and former senior editor, personal finance, of Investopedia.

Lea Uradu, J.D. is a Maryland State Registered Tax Preparer, State Certified Notary Public, Certified VITA Tax Preparer, IRS Annual Filing Season Program Participant, and Tax Writer.

Suzanne is a content marketer, writer, and fact-checker. She holds a Bachelor of Science in Finance degree from Bridgewater State University and helps develop content strategies for financial brands.

What Is a Tax Identification Number (TIN)?

A Tax Identification Number (TIN) is a nine-digit number used by the Internal Revenue Service (IRS) to identify taxpayers. Also known as a taxpayer identification number, one type of TIN includes Social Security numbers (SSNs) issued by the Social Security Administration (SSA).

Key Takeaways

• Tax identification numbers are nine-digit tracking numbers used by the IRS.
• The IRS issues all U.S. tax I.D. numbers except for Social Security numbers, issued by the Social Security Administration.
• Tax filers must include their TIN on tax-related documents and when claiming benefits.

Types of Tax Identification Numbers (TIN)

• Social Security number (SSN): The most common tax identification number issued to U.S. citizens, permanent residents, and certain temporary residents by the Social Security Administration. These numbers are formatted as XXX-XX-XXXX. The SSN is required to secure legal employment in the U.S. and to receive Social Security benefits and other government services.
• Individual Taxpayer Identification Number (ITIN): Issued by the Internal Revenue Service (IRS) to certain nonresident and resident aliens, their spouses, and their dependents when they're ineligible for SSNs. They're arranged in the same format as an SSN (XXX-XX-XXXX). The Individual Taxpayer Identification Number (ITIN) always begins with a 9. The applicant must complete Form W-7 and submit documents supporting their resident status to get an individual tax ID number.
• Employer Identification Number (EIN): Used by the IRS to identify corporations, trusts, and estates that must pay taxes. Just like SSNs, employer tax ID numbers are nine digits but they're read as XX-XXXXXXX. Those who qualify for an Employer Identification Number (EIN) must apply for and use it to report their capital gains and income for taxation purposes.
• Adoption Tax Identification Number: The ATIN applies to domestic adoptions when the adoptive parents cannot obtain the child's SSN to complete their tax returns. The child must be a U.S. citizen or permanent resident to qualify and the adoption must be pending.
• Preparer Tax Identification Number: The IRS requires a PTIN on each tax return filed. Any tax preparer who charges to complete all or part of a tax return for another individual must have and use a PTIN.
  

A child must have an SSN before a parent can claim them as a dependent for income tax purposes so parents voluntarily apply for the number on behalf of their children.

When Is a TIN Required?

A taxpayer identification number identifies individuals, corporations, and entities such as nonprofit organizations (NPOs). The TIN is mandatory for anyone filing annual tax returns with the IRS and the agency uses it to track taxpayers. A taxpayer identification number is required:

• For credit: Banks and other lenders require Social Security numbers on credit applications. This information is then relayed to the credit bureaus to ensure that the right person fills out the application. The credit reporting agencies also use TINs, notably SSNs, to report and track an individual's credit history.
• For employment: Employers require an SSN from anyone applying for employment. This ensures that the individual is authorized to work in the United States. Employers verify the numbers with the issuing agency.
• For state agencies: Businesses also require state identification numbers for tax purposes to file with their state tax agencies. State taxing authorities issue the I.D. number directly to the filer.

The abbreviation TIN stands for "tax identification number" or "taxpayer identification number."

Global TINs

Almost every country uses TINs for various reasons. Canada uses Social Insurance Numbers (SINs) for employment, tax, benefits, and credit purposes. The SIN is a nine-digit unique identifier that's formatted as XXX-XXX-XXX. Countries in the European Union also use TINs that help government agencies identify taxpayers and allow entities to invest money across the Union.

Who Needs a Tax Identification Number?

To work in the United States or file taxes with the IRS, individuals need a TIN. A taxpayer identification number allows individuals to take advantage of benefits or services offered by the government, run their day-to-day business operations, and report their taxes.

Are TINs Available Online?

The agency that issues a TIN will provide individuals with an official document with their unique identifier. TINs are not available online because they are considered sensitive information.

Is a Taxpayer Identification Number the Same as a Social Security Number?

A Social Security number is an example of a TIN. It allows individuals to seek employment in the United States, to obtain credit with banks and other lenders, and file income tax returns.

The Bottom Line

A taxpayer identification number or TIN is necessary to work in the United States and file a tax return. Individuals can get a Social Security number through the Social Security Administration or obtain an Individual Taxpayer Identification number or a number for a business directly from the IRS.

1. Social Security Administration. "Social Security Number & Card."
2. IRS. "Individual Taxpayer Identification Number."
3. IRS. "Employer ID Numbers."
4. IRS. "Adoption Taxpayer Identification Number."
5. IRS. "PTIN Requirements for Tax Return Preparers."
6. IRS. "Qualifying Child Rules."
7. IRS. "U.S. Taxpayer Identification Number Requirement."
8. Government of Canada. "Social Insurance Number Overview."
9. European Commission. "TIN-Taxpayer Identification Number."

A qualified higher education expense is a tax credit for the parents of students attending a college or other post-secondary institution.

A filing extension is an exemption made for taxpayers who are unable to file their federal tax return by the regular due date.

A widow(er)'s exemption is one of several forms of state or federal tax relief available to a surviving spouse in the period following their spouse's death.

Unrecaptured Section 1250 gain relates to an IRS tax rule directing that depreciation be recaptured when a gain is realized on the sale of depreciable real estate.

A private letter ruling is an IRS interpretation of rules and their application in response to a particular taxpayer's complex set of circumstances.

A flow-through entity is a legal business entity that passes income to the owners and/or investors of the business. It's sometimes referred to as a disregarded entity.

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