If you need to file a tax return, you may be experiencing some confusion surrounding exactly what a TIN is. A Taxpayer Identification Number, or TIN, is a nine-digit identifier issued by the IRS or SSA to track individuals and businesses obligated to pay taxes in the United States. 

This post will give a more accurate breakdown of the different types of TINs and their distinct purposes.

The different types of Tax Identification Numbers


A Social Security Number (SSN) is a crucial nine-digit identifier issued to U.S. citizens, permanent residents, and temporary (working) residents. Its primary function is for Social Security tracking, and it’s vital for purposes like employment, tax filing, and government benefits. Obtaining an SSN involves completing Form SS-5, and providing documentation of identity, age, and U.S. citizenship or lawful alien status.


The Individual Taxpayer Identification Number (ITIN) is designed for individuals who need a U.S. taxpayer identification number but aren’t eligible for an SSN. To get an ITIN, you need to complete IRS Form W-7, substantiating foreign/alien status and true identity. 


An Employee Identification Number (EIN) is a nine-digit identifier assigned by the IRS to various business entities operating in the U.S. This includes employers, sole proprietors, corporations, partnerships, non-profit organizations, trusts, estates, government agencies, certain individuals, and other business entities. Applying for an EIN is possible online using the IRS portal and filling out Form SS-4.


An ATIN is an Adoption Taxpayer Identification Number issued by the Internal Revenue Service as a temporary taxpayer identification number for the child in a domestic adoption where the adopting taxpayers do not have and/or are unable to obtain the child’s Social Security Number (SSN). The ATIN is to be used by the adopting taxpayers on their federal income tax return to identify the child while final domestic adoption is pending.


For paid tax return preparers, the Preparer Taxpayer Identification Number (PTIN) serves as a unique identifier. It’s mandatory for all paid tax preparers and professionals to include a valid PTIN on their and, if relevant, their client’s returns. If you need one obtaining a PTIN involves using the IRS sign-up system or completing Form W-12.

TINs in different countries

While this information pertains specifically to the TIN rules in the U.S., it’s worth noting that other countries have their own variations of TINs. The specifics vary, so for comprehensive details in different countries, one would need to refer to the respective tax authorities. Before filing your tax return, it’s helpful to conduct your own research about the tax rules in a specific country. 

The TIN system is not global. Similarly, you may need different information for different states, however, professional consultants will be able to advise on the information you need if you are unsure. 

How do I look up my TIN?

Curious about your TIN or need to verify one? Consider using EINsearch, a reliable platform for TIN lookup services. Whether you’re an individual or a business, EINsearch simplifies the process of finding EINS, or validating TINs (SSN or EIN) with a user-friendly interface. 

Our extensive database allows you to access all the information you need to validate your TIN before filing your tax return. This can help you prevent any errors in your tax returns which can help prevent delays and therefore penalties. This is especially important for businesses that deal with larger, more complex tax returns. 

If you need assistance with EIN lookups or TIN verifications, don’t hesitate to get in touch with EINsearch today. We will happily answer any queries you may have pertaining to TIN verification or EIN searches. 

Final thoughts

Understanding the different types of TINs is essential for individuals and businesses who need to exercise tax compliance during their tax returns. Each TIN serves a unique purpose, ensuring accurate tracking and adherence to IRS regulations on both individual and corporate levels. Whether you’re an employer, taxpayer, or adoptive parent, knowing the right TIN for your situation is the key to smooth and compliant interactions with the IRS. 

If you need to perform an EIN lookup, EINsearch provides a convenient solution, ensuring accuracy and peace of mind in your tax-related needs. Our packages are affordable and tailored to your individual needs.