ITIN vs SSN: Understanding the Key Differences

When navigating the complexities of the U.S. tax system or even trying to understand identity numbers used within the country, two acronyms stand out: ITIN and SSN. Both the Individual Taxpayer Identification Number (ITIN) and the Social Security Number (SSN) are crucial components of the American identification system. However, the purpose, eligibility, and application processes for each differ substantially. This post aims to demystify the differences between ITIN vs SSN.

What is an Individual Taxpayer Identification Number (ITIN)?

The ITIN, or Individual Taxpayer Identification Number, is a tax processing number issued by the Internal Revenue Service (IRS). It’s crucial to understand that an ITIN does not grant legal status in the U.S. or provide eligibility for Social Security benefits.

The primary purpose of the ITIN is to facilitate tax payment by foreign nationals and others who have tax obligations in the U.S. but do not qualify for a Social Security Number. These individuals might include:

  • Non-resident aliens filing a U.S. tax return.
  • U.S. resident aliens filing a U.S. tax return.
  • Dependent or spouse of a U.S. citizen/resident alien.
  • Dependent or spouse of a non-resident alien visa holder.

What is a Social Security Number (SSN)?

On the other hand, the Social Security Number (SSN) is a nine-digit number issued to U.S. citizens, permanent residents, and temporary working residents. The issuance is by the Social Security Administration (SSA). The primary purpose of an SSN was to track individuals for Social Security benefits. However, over time, it has become a de facto identification number for taxation and other purposes.

Having an SSN not only facilitates participation in the Social Security system but also makes individuals eligible for other services and benefits. An SSN is typically required for:

  • Employment in the U.S.
  • Opening a bank account.
  • Applying for federal benefits.
  • Obtaining certain types of licenses.
  • Serving as an ID for various purposes.

ITIN vs SSN: The Key Differences

  1. Purpose: As highlighted, the ITIN is predominantly for tax processing for those ineligible for an SSN, while the SSN is broader in scope, serving both tax and identification purposes.
  2. Eligibility: Any foreign national or non-resident with U.S. tax obligations can apply for an ITIN. On the contrary, only U.S. citizens, permanent residents, and specific non-immigrants can obtain an SSN.
  3. Issuing Authority: The IRS issues the ITIN, whereas the SSA is responsible for providing the SSN.
  4. Benefits: Holding an ITIN does not provide Social Security benefits or make one eligible for employment in the U.S. Meanwhile, an SSN is crucial for employment and can grant access to Social Security benefits.
  5. Expiration: ITINs may expire if not used on a federal tax return at least once in three consecutive years. Some ITINs have an expiration date. However, SSNs are permanent and do not expire.


In the grand scheme of ITIN vs SSN, it’s evident that while both numbers are integral to the U.S. system, they cater to different demographics and have varied uses. Understanding these differences is crucial for individuals looking to work, live, or fulfill tax obligations in the U.S.