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4 min read

SSN vs ITIN: What’s The Difference?

SSN vs ITIN: What’s The Difference? 

SSNs and ITINs both serve as taxpayer ID numbers. So, what exactly is the difference between the two? Learn more with RemotePad.

First things first: an ITIN is not the same as an SSN. 

People often use the two terms interchangeably. It’s an understandable mix-up given the fact that they both serve a similar purpose as taxpayer ID numbers. 

However, different government agencies issue each ID number to distinct groups of people. 

While both ID numbers are used for tax purposes, an SSN can serve as a means of identification in ways an ITIN cannot. 

Let’s dive into what each ID number is used for, who uses it, and why it’s important for global employment.  


What is the difference between a Social Security Number (SSN) and an ITIN?

There are four main differences between a Social Security Number and an Individual Taxpayer Identification Number: 

  1. Administrative agency: A different administrative agency issues each ID number.
  2. Who uses which: Different groups of people have either an SSN or an ITIN; it’s not possible to have both.
  3. Purpose: Both numbers are used for tax purposes. However, SSNs can function as proof of identity for other government agencies and programs. 
  4. Expiration: ITINs are valid for five years; Social Security Numbers do not expire. 

An SSN is a Social Security Number issued by the Social Security Administration (SSA). SSNs are assigned in one of two ways:

  1. The SSA automatically issues them at birth to people born in the United States, or
  2. People seeking authorization to work in the US (permanent workers, temporary workers, and international students) can apply.

An ITIN is an Individual Taxpayer Identification Number issued by the IRS. ITINs are tax processing numbers for foreign nationals, undocumented immigrants, nonresident individuals, their spouses, and other dependents who can’t get an SSN but still need to pay taxes.

ITIN and SSN are not to be confused with EIN either. 

What is an ITIN used for? 

ITINs allow individuals who can’t otherwise obtain an SSN to file federal taxes in the United States. 

However, ITINs do not authorize a person to work or live in the country. ITINs can also be used to open an interest-bearing bank account. 

ITINs are essential to people who must remain compliant with US tax law, including undocumented and nonresident individuals who work in the country. 

ITINs may also be applicable for foreign entities involved in real estate transactions, trusts, or partnerships. 

If someone has lost their ITIN or wishes to check its status, they can call the IRS toll-free line at 1-800-829-1040. 

The holder must answer a series of questions from the IRS to verify their identity before retrieving the ITIN.

Individuals seeking an ITIN must complete the following steps: 

  1. Form W-7, IRS Application for Individual Taxpayer Identification Number
  2. Submit federal income tax documents (e.g., Form 1040)
  3. Provide supplementary documentation such as a passport, ID cards, or proof of United States residency
  4. Submit your application and supporting documents to the IRS (either via mail or in-person at an IRS Taxpayer Assistance Center)

What is a Social Security Number used for?

SSNs serve as both a taxpayer ID number and a means for personal identification for United States citizens and those authorized to work in the country. 

While SSNs are primarily used for tax purposes, they’re also essential to use many other services and government programs, such as:

  • Applying for a job
  • Enrolling in Medicare
  • Applying for a driver’s license
  • Opening an account with a US financial institution
  • Applying for a federal loan
  • Applying for unemployment benefits or Social Security disability income
  • Applying for a passport

If you lost your Social Security card, which states your Social Security Number, you must apply for a replacement card from the SSA. For security purposes, the SSA does not provide SSNs in any other manner. 

To apply for a replacement card, you can apply online at my Social Security account. Or, you can also fill out Form SS-F and take it to a Social Security office near you. 

So, how do you know if you have an SSN or an ITIN?

Simply put, nobody in the United States should have both an SSN and an ITIN. 

United States citizens and authorized noncitizens who have permission to work in the country have Social Security Numbers.

Residents with foreign status and undocumented immigrants that need to file a tax return have an ITIN. 

If you are unsure of whether you have an SSN or an ITIN, you can tell by the formatting of the number. 

While both serial numbers have nine digits in the following format: XXX-XX-XXXX, the first number of an ITIN starts with a nine, and the fourth number begins with 7: 9XXX-7X-XXXX. 

Can I work legally with an ITIN?

While ITINs can be used to file taxes, they do not provide authorization for the following:

  • Legal immigration status
  • Legal work authorization
  • Qualification for the Earned Income Tax Credit
  • Social Security Number eligibility 
  • Social Security benefits 

Even if someone applies for a job with an ITIN, the employer can easily look up the applicant in a government database to verify that they have an SSN. 

Can I use my ITIN as a Social Security Number?

ITINs can take the place of an SSN to file a federal tax return. However, this only applies to people who do not have or cannot obtain an SSN.

Furthermore, ITINs cannot take the place of SSNs as proof of identification for non-tax purposes. 

Conclusion: SSNs vs. ITINs

Social Security Numbers and Individual Taxpayer Identification Numbers both fall under the umbrella of tax IDs. 

However, individuals can only have one or the other when it comes to SSNs and ITINs, and the two numbers serve distinct groups of people:

  • The IRS issues ITINs to nonresidents, their spouses and dependents, and others who cannot obtain an SSN
  • The SSSA issues SSNs to US citizens and legally authorized workers 

Knowing which one you have and what it can be used for is key to filing and paying taxes in the US. 

Tamsin is RemotePad’s careers, travel and global work specialist. Currently based in London, Tamsin holds a Bachelor’s from Middlesex University, and a Master’s from the London Metropolitan University. Tamsin has previously written for a variety of prominent travel outlets and job sites.