ITIN for foreigners: what it is, who needs one and how to apply

The ITIN shows up in almost every process a foreigner goes through in the U.S.: opening an account, forming an LLC, filing taxes or selling a property. And almost always with the same question: do I need one? Often the answer is no, or not yet. Here is what it is, who really needs it, how to apply and the mistakes that get applications rejected by the IRS, based on the official instructions.

What an ITIN is and isn't

The ITIN (Individual Taxpayer Identification Number) is a nine-digit tax ID issued by the IRS. It has the same format as a Social Security number. It exists so that people who need to meet U.S. tax obligations, and aren't eligible for an SSN, can do so, regardless of immigration status.

According to the IRS, an ITIN is issued for federal tax purposes only. So it helps to be clear about what it does not do:

• It doesn't authorize you to work in the U.S.
• It doesn't give or change any immigration status.
• It doesn't qualify you for Social Security benefits or the Earned Income Tax Credit (EITC).
• It isn't an ID outside the federal tax system.

You also can't hold an ITIN and an SSN at the same time. If you later get a Social Security number, stop using the ITIN and tell the IRS so it can merge your records.

Who needs one and who doesn't

You need an ITIN if you have a federal tax obligation or benefit and can't get an SSN. The most common cases:

• You are a nonresident alien who must file a U.S. tax return, for example because you have income connected with a business in the country.
• You are a resident for tax purposes who must file but isn't eligible for an SSN.
• You are the spouse or dependent of a citizen or resident who includes you on their return.
• You want to claim a tax treaty benefit between your country and the U.S. to reduce withholding.

According to the IRS, you don't need one if you are a U.S. citizen, a green card holder or eligible for an SSN, for example because your visa or permit allows you to work. In that case, apply for a Social Security number, not an ITIN.

Do you need one for your LLC or bank account?

This is the most common mix-up. In many cases, no:

• To form the LLC and get its EIN, the company's tax ID, you don't need an ITIN. We cover this in our guide on how to open a Florida LLC as a non-resident.
• For the information return of a single-member LLC owned by a foreigner (Form 5472), the IRS instructions ask for the owner's U.S. tax number "if any." Without one, a reference ID number is used instead. See our Form 5472 guide.
• To open a bank account, federal rules let banks identify you with your passport. Some ask for an ITIN or SSN as their own policy, but it isn't a legal requirement. See how to open an account without an SSN.

The reverse is also true: the IRS won't issue an ITIN just so you can open an account. The exceptions that allow one without a return are limited to specific cases, such as accounts that generate income connected with a U.S. business, and they require an original letter from the bank.

Where the ITIN usually does appear is later: if your LLC has income that requires you to file a personal U.S. return, typically Form 1040-NR, you will need an ITIN and will apply for it with that return. Whether that obligation applies to you is a question for an accountant.

How to apply: Form W-7

You apply for an ITIN with Form W-7 (December 2024 revision). The general rule is to send it together with your federal tax return, not separately, and by that return's due date. The IRS doesn't charge for processing it.

The package usually includes:

1. The completed Form W-7, with your reason for applying checked.
2. Your federal tax return, unless you qualify for an exception.
3. Documents proving your identity and foreign status, originals or copies certified by the issuing agency.

On the form you will enter your address in the country where you permanently or normally reside. If you mail it, your original documents will be returned to the address you enter on line 2.

When you can apply without a tax return

In some cases you don't have to file a return but still need an ITIN because someone must report to the IRS or withhold tax from you. The W-7 instructions list five exceptions. The most relevant for people with interests in Miami:

Each exception requires specific documents that prove the situation, such as a bank letter, the partnership agreement or the withholding forms. The fifth applies to representatives of foreign corporations with electronic filing requirements.

Documents that prove your identity

The IRS accepts thirteen types of documents, but one makes everything simpler: a valid passport. It is the only document that proves both your identity and foreign status on its own. Without it, you must submit at least two documents from the list, and one must have a photo.

What matters is the format: the IRS requires originals or copies certified by the issuing agency. A notarized photocopy doesn't count. That is why many people prefer not to mail their passport and choose one of the in-person routes.

Three ways to submit

The IRS publishes the official list of certifying acceptance agents, grouped by state in the U.S. and by country abroad. On that list, entries marked with an asterisk are acceptance agents, who help with the form but can't certify your documents: with them you would still have to mail the originals. If you want to keep your passport, choose one without an asterisk.

There is a fourth option with limited availability: some free tax help sites (VITA) have certifying acceptance agents. If you're in South Florida, see where to get an ITIN in Miami, with the local offices, sites and agents.

Timing, expiration and renewal

• Response time: the IRS says to allow about 7 weeks to hear back, and 9 to 11 weeks if you apply during tax season (January 15 to April 30) or from abroad.
• Expiration: if your ITIN isn't on at least one federal return for three consecutive years, it expires on December 31 of the third year.
• Renewal: you only need to renew if it has expired and you need to file a return again. You use the same Form W-7, checking the renewal box.
• If you need an extension or want to make estimated payments before you have an ITIN, you can: the IRS says to write "ITIN TO BE REQUESTED" in the number field.

Watch out for tax credits: to claim some of them, your ITIN and those of your spouse or dependents must be assigned by the return's due date. Apply late and you may lose them.

Common mistakes

1. Applying for an ITIN when you're eligible for an SSN. The IRS won't issue it, and it delays everything else.
2. Applying without a tax reason. An ITIN isn't issued "just in case" or just to open an account.
3. Sending the W-7 without a tax return when no exception applies.
4. Sending photocopies or notarized copies. They must be originals or copies certified by the issuing agency.
5. Using the address for tax returns. ITIN applications go to their own address in Austin, Texas.
6. Letting it expire without noticing. Three years without using it on a return and you'll have to renew.

Frequently asked questions

Next step

The ITIN is one more piece of the puzzle: first the company, then the account and, when there is a tax obligation, the number to meet it. If you're just starting, review how to open your LLC and where to open your account. And if you'd like someone to look at your case, inMiami.ai is building a network of independent accountants and professionals in Miami, in English and Spanish.