Skip to content

What’s the Difference Between an ITIN and a Social Security Number?

In the realm of U.S. taxation, compliance is paramount. Yet, for individuals without a Social Security Number (SSN), a crucial identification requirement, obtaining an Individual Tax Identification Number (ITIN) becomes essential. So, what's the difference between an ITIN and a social security number? If your employees seek clarity on ITINs, here's a comprehensive guide to enlighten them.

Schedule a free consultation!

Decoding ITIN

An Individual Tax Identification Number (ITIN) is a unique identification issued by the Internal Revenue Service (IRS) to individuals who either lack eligibility for or possess a Social Security Number (SSN). Remarkably, ITINs are granted without regard to immigration status, making them a vital instrument for various tax-related purposes.

Distinguishing ITIN from SSN

While ITIN and Social Security Number (SSN) consist of nine digits in the format of xxx-xx-xxxx, they are far from interchangeable. Let's delve into the distinctions:

Specific Purpose: An ITIN is exclusively designed for federal tax reporting, serving no other functions. It neither confers work authorization in the United States nor makes individuals eligible for Social Security benefits.

SSN's Versatility: On the contrary, an SSN is primarily allocated to U.S. citizens and authorized residents. It is pivotal in enabling employers to report their employees' income to the IRS and their Social Security wages to the Social Security Administration. Furthermore, an SSN facilitates various personal endeavors such as opening bank accounts, securing credit or private insurance, and even purchasing real estate.

Taxation: Employers utilize an individual's SSN to fulfill state income tax obligations in applicable states, whereas an ITIN does not extend to this realm.

Numeric Distinction: An essential numerical distinction lies in the fact that ITINs always commence with the digit '9'.

Applying for an ITIN

For employees in need of an ITIN, the process begins with the completion of Form W-7, aptly titled "Application for IRS Individual Taxpayer Identification Number." It is imperative to note that holding both a Social Security Number and an ITIN is strictly prohibited.

Furthermore, individuals possessing an ITIN must be aware of critical IRS regulations. ITINs are subject to expiration if they remain dormant on federal income tax returns for five consecutive years. Hence, periodic usage is pivotal to maintaining the validity of this tax identifier.

By disseminating this comprehensive information to your employees, you equip them with a clear understanding of the significance and distinctions between ITINs and SSNs. In the complex world of U.S. taxation, knowledge is power, and ensuring compliance is paramount for both individuals and organizations alike.


Whether you've been in the payroll industry long or just barely starting it's important to keep these small but mighty details in mind regarding ITIN and Social Security. If you are interested in learning more about our Payroll & HR Services contact us at 909.466.7876 for a free live demonstration!

Also, learn about the Updates and Reminders for Employee Leave Laws for 2024! Or, if you're looking to hire someone new for your payroll department have you wondered Who Should be the Payroll Manager? Find out here!