SSN vs ITIN — What Immigrants Need to Know for Taxes

Two Numbers That Determine How You File

When immigrants begin to navigate the U.S. financial and tax system, one of the first confusing moments involves a simple question that appears on almost every important form: “What is your taxpayer identification number?”

For many people who were born and raised in the United States, this question has an automatic answer. They have a Social Security Number and have used it since childhood. The question barely registers.

For immigrants, the question can stop everything. Do you need a Social Security Number to file taxes? Can you use an ITIN instead? Are they the same thing? Does one affect the other? Can you have both?

These questions matter enormously. Getting the wrong answer can mean filing taxes incorrectly, missing refunds you are entitled to, or creating complications that affect both your finances and your immigration case.

This guide will explain the difference between a Social Security Number and an Individual Taxpayer Identification Number, who needs each one, how to get them, and exactly how they affect the way immigrants file taxes in the United States.

What Is a Social Security Number?

A Social Security Number, or SSN, is a nine-digit number issued by the U.S. Social Security Administration. It was originally created to track workers’ earnings and calculate Social Security retirement benefits, but over time it has become the primary identification number used across the American financial and administrative system.

Your SSN is used for:

• Filing federal and state tax returns
• Opening bank accounts
• Applying for credit cards and loans
• Employment verification
• Accessing government benefits
• Many other financial and legal processes

Who is eligible for a Social Security Number:

Social Security Numbers are issued to U.S. citizens, U.S. nationals, and certain immigrants who are authorized to work in the United States. This includes:

• U.S. citizens by birth or naturalization
• Lawful permanent residents (green card holders)
• Immigrants authorized to work on certain visa types, including H-1B, L-1, O-1, TN, E-3, and others
• Certain refugees and asylum seekers

If you are authorized to work in the United States, you are generally eligible to apply for a Social Security Number. The application is made through the Social Security Administration, and you will need to provide documentation of your identity, age, and immigration status.

When you cannot get an SSN:

Not all immigrants are eligible for a Social Security Number. If you are in the United States but not authorized to work — for example, on certain visa types, on a tourist visa, or in an undocumented status — you are not eligible for an SSN.

This does not mean you have no tax obligations. Many people who are not eligible for an SSN still have income in the United States and are required by law to file tax returns. For these individuals, the IRS created a separate identification system: the Individual Taxpayer Identification Number.

What Is an Individual Taxpayer Identification Number (ITIN)?

An Individual Taxpayer Identification Number, or ITIN, is a nine-digit number issued by the Internal Revenue Service specifically for tax purposes. It is issued to individuals who have a U.S. tax filing or reporting requirement but are not eligible for a Social Security Number.

ITINs always begin with the number 9, which distinguishes them from Social Security Numbers.

Who uses an ITIN:

• Immigrants who have income in the United States but are not authorized to work (for example, certain visa holders whose visa type does not permit employment but who have investment income or other U.S.-source income)
• Undocumented immigrants who earn income and are required to pay taxes
• Foreign nationals who have U.S. tax filing obligations due to investments, rental income, or other U.S.-source income but do not live in the United States
• Spouses and dependents of U.S. citizens or residents who need to be listed on a tax return but who are not eligible for SSNs

What an ITIN is used for:

An ITIN is used exclusively for tax purposes. It allows people without SSNs to:

• File federal tax returns
• Pay taxes on U.S.-source income
• Be claimed as a dependent or spouse on another person’s tax return
• Open certain bank accounts
• Apply for certain financial products (many banks and some brokerages accept ITINs)

What an ITIN cannot do:

An ITIN is not a work authorization document. It cannot be used to verify employment eligibility or to obtain a Social Security card. It does not establish immigration status or authorize a person to work in the United States. It does not entitle the holder to Social Security benefits, the Earned Income Tax Credit in most circumstances, or other benefits reserved for those with valid SSNs.

A Critical Point: Everyone With U.S. Income May Have a Tax Obligation

One of the most important things for immigrants to understand about the U.S. tax system is this: your obligation to pay taxes in the United States is based on your income, not on your immigration status or documentation.

Many immigrants believe — incorrectly — that if they do not have a Social Security Number, or if they are undocumented, they do not need to pay taxes. In fact, the IRS requires anyone with income above certain thresholds to file a tax return and pay applicable taxes, regardless of immigration status.

The IRS and immigration authorities are separate agencies. The IRS’s role is tax collection, not immigration enforcement. Filing a tax return with the IRS does not trigger immigration consequences. In fact, filing taxes often creates a documented record of presence and compliance that can support immigration applications.

Immigrants who work in the United States and earn income — including those without documentation — are required to file taxes and pay what is owed. The ITIN exists specifically to allow people without SSNs to meet this obligation legally.

How to Apply for a Social Security Number

If you are eligible for an SSN, applying for one is an important early step.

Where to apply: Applications are made at your local Social Security Administration (SSA) office. You can find your nearest office on the SSA website.

What documents you will need:

• Proof of identity (such as a passport)
• Proof of your immigration status and work authorization (such as your visa, I-94 arrival record, or employment authorization document)
• Proof of age

All documents must be originals or certified copies. The SSA will not accept photocopies.

Timing: Some immigrants are able to request an SSN as part of the visa application process. Others must apply after arriving in the United States. In general, it is advisable to wait until you have actually arrived and your immigration documents are current before applying.

Processing time: After submitting your application, it typically takes two to four weeks to receive your Social Security card by mail.

How to Apply for an ITIN

If you are not eligible for a Social Security Number but have U.S. tax obligations, applying for an ITIN is a necessary step.

The application form: You apply for an ITIN using IRS Form W-7, titled “Application for IRS Individual Taxpayer Identification Number.” This form is available on the IRS website.

What you need to submit with Form W-7:

You must provide documentation that proves two things: your foreign status and your identity. A passport is the most straightforward document because it proves both at once. Other combinations of documents can also satisfy the requirement.

You must also typically submit a completed federal tax return with your W-7 application, unless you qualify for one of the specific exceptions listed on the form.

How to submit your application:

There are three options for submitting your ITIN application:

By mail. Send your completed Form W-7, your tax return, and your original identity documents to the IRS ITIN Operations center. Note that submitting original identity documents by mail carries some risk, as documents can be lost. The IRS does have a process for returning documents, but this method requires care.

In person at an IRS Taxpayer Assistance Center. You can bring your documents to an IRS office for in-person review. Staff can certify your documents and submit the application, which means you do not have to mail original documents.

Through a Certified Acceptance Agent (CAA). A Certified Acceptance Agent is a person or organization authorized by the IRS to assist with ITIN applications. They can review your original documents, certify copies, and submit the application on your behalf. Many tax preparation services, community organizations, and legal aid organizations are Certified Acceptance Agents. This is often the most practical option for immigrants who are unfamiliar with the process.

Processing time: ITIN applications typically take seven to eleven weeks to process during tax season and less time during off-peak periods.

ITIN expiration: ITINs can expire if they are not used on a federal tax return for three consecutive years, or due to IRS changes to certain ITIN ranges. If your ITIN has expired, you will need to renew it before filing your taxes. You can check whether your ITIN is current on the IRS website.

What Happens If You Get an SSN After Having an ITIN?

This situation is common for immigrants whose status changes. For example, you may have used an ITIN to file taxes while on a visa type that did not authorize work, and then later received work authorization and obtained an SSN.

When this happens, you should notify the IRS so that your prior tax filings can be associated with your new SSN. You do this by writing to the IRS and providing both your ITIN and your new SSN. Once your records are updated, you should use your SSN going forward and no longer use your ITIN.

You should also notify your employer and any financial institutions of your new SSN.

The Earned Income Tax Credit and ITIN

One important limitation of ITINs is worth understanding: people who file taxes using an ITIN are generally not eligible for the Earned Income Tax Credit, or EITC.

The EITC is a significant tax benefit available to lower and moderate-income workers. For workers with children, it can be worth thousands of dollars per year. However, it is available only to people who file with a valid Social Security Number.

If you have been filing with an ITIN but later obtain an SSN, you may be able to go back and claim the EITC for prior years when you had earned income and had a valid SSN. The rules for this are specific and a tax professional can help you determine whether you qualify for any back credits.

Children of Immigrants: SSN vs ITIN

Children who are born in the United States are U.S. citizens and are eligible for Social Security Numbers at birth. If you have a child born in the U.S., you can request an SSN for your child at the hospital when they are born, or afterward through the Social Security Administration.

Children who were born outside the United States and who do not have legal status that would qualify them for an SSN can be listed on their parent’s tax return using an ITIN, if they meet the dependency requirements.

If you are claiming children as dependents on your tax return, it is important to have the correct identification number — SSN or ITIN — for each child listed.

Protecting Your SSN and ITIN

Both your Social Security Number and your ITIN are sensitive pieces of personal information. In the wrong hands, they can be used for identity theft and financial fraud.

Protect these numbers carefully:

• Do not carry your Social Security card in your wallet. Keep it in a secure location at home.
• Do not share your SSN or ITIN over the phone or by email unless you initiated the contact with a trusted institution.
• Be aware of IRS impersonation scams. The IRS primarily communicates by mail. If someone calls claiming to be from the IRS and demands immediate payment or personal information, this is almost certainly a scam. Hang up and call the IRS directly using the number on their official website.
• Review your tax transcripts annually to ensure no one has filed a fraudulent return using your identification number.

Conclusion: The Right Number Makes Everything Easier

Understanding the difference between an SSN and an ITIN, knowing which one applies to your situation, and having the correct number in hand before tax season begins makes the entire tax filing process significantly simpler and less stressful.

If you are eligible for a Social Security Number, apply for one as soon as possible. If you are not eligible and have U.S. income or tax obligations, apply for an ITIN using Form W-7 before you need to file your first return.

In our next guide, we will walk through the complete step-by-step process of filing your taxes as an immigrant in the United States — from gathering your documents to submitting your return.