Taxpayer Identification Number (TIN)

A Taxpayer Identification Number, or TIN, is the identifying number the US tax system uses to match income, filings, and payments to the right person or entity. The IRS defines a TIN as “an identification number used by the Internal Revenue Service (IRS) in the administration of tax laws,” and explains the full set on its Taxpayer Identification Numbers page. It is not a single number. It is a family of five different numbers, and which one applies depends on who you are and why you need it.

The Five Types of TIN

The IRS recognizes five Taxpayer Identification Numbers. One is issued by the Social Security Administration, and the rest are issued by the IRS. The IRS states that “a Social Security number (SSN) is issued by the SSA whereas all other TINs are issued by the IRS.”

• Social Security Number (SSN). Issued by the Social Security Administration to US citizens and certain authorized residents. It is the most common TIN for individuals.
• Individual Taxpayer Identification Number (ITIN). Issued by the IRS to certain nonresident and resident aliens, their spouses, and dependents who cannot get an SSN.
• Employer Identification Number (EIN). Issued by the IRS to identify a business entity. It is also used by estates and trusts.
• Adoption Taxpayer Identification Number (ATIN). A temporary number issued by the IRS for a child being adopted when the adopting taxpayer cannot get an SSN for the child in time to file.
• Preparer Taxpayer Identification Number (PTIN). Required for paid tax return preparers, who must use it on the returns they prepare.

When a TIN Is Required

The IRS states that “a TIN must be furnished on returns, statements, and other tax related documents.” Two of the situations it names are “when filing your tax returns” and “when claiming treaty benefits.” For anyone engaging or paying a contractor, the TIN is what links the payment to the correct taxpayer record at year-end.

Which TIN a Contractor or Payer Uses

The right TIN depends on whether the worker is a US person or a foreign person.

• A US person on Form W-9. A US contractor or business certifies its TIN on Form W-9 so the payer can issue the correct information return. An individual or sole proprietor generally uses an SSN, and a registered business entity uses an EIN.
• A foreign person on Form W-8BEN. A foreign individual documents foreign status on Form W-8BEN. To claim a reduced rate under an income tax treaty, the IRS requires a TIN to be furnished. That can be a foreign tax identifying number from the person’s home country, or a US ITIN where one is required.

In short, a US payee gives an SSN or EIN, and a foreign payee gives a foreign TIN or US ITIN to unlock treaty benefits.

Related Terms

• ITIN: the IRS-issued TIN for individuals who cannot get an SSN.
• EIN: the TIN that identifies a business entity.
• Form W-9: how a US person certifies its TIN to a payer.

Omnivoo Contract Management collects the correct TIN on the right form for each contractor, US persons on Form W-9 and foreign persons on Form W-8BEN, so payments map cleanly to year-end tax reporting.