Can I file a 1040 or do I have to file a 1040-NR?

If you're required to file a federal return for 2024, you can use Form 1040 (US Individual Income Tax Return) if any of these are true:

• You're a US citizen.
• You're a resident of the US or Puerto Rico.
• You have a Permanent Resident Card ("green card").
• You're a nonresident alien married to a US citizen/resident alien with whom you'll file a joint return.
• You meet the substantial presence test, and were physically present in the US for at least 31 days in 2024 and for at least 183 days from 2022 to 2024. To meet this requirement, you must calculate and add the following:
  • All the days you were present in 2024
  • 1/3 of the days you were present in 2023
  • 1/6 of the days you were present in 2022

Here's the formula for this calculation:

2024 days + (2023 days)/3 + (2022 days)/6 >= 183

Example: Joe works three months (90 days) every summer as a camp counselor in the US. Joe meets the first part of the test (at least 31 days in 2024), but fails the 183-day test:

31 + 90/3 + 90/6 = 31+30+15 = 76 days

Because Joe didn't meet the substantial presence test, Joe's considered a nonresident alien for federal tax purposes and can't file a 1040. Instead, Joe must file a 1040-NR.

In addition to those who don't pass the substantial presence test, nonresident aliens also include:

• Foreign nationals
• Anybody who isn't a US citizen, US or Puerto Rico resident alien, or doesn't hold a green card
• A person who has income from or participates in a US-sourced trade or business

Unlike the 1040, there's no minimum income threshold for filing a 1040-NR. In other words, nonresident aliens with US income, regardless of amount, are required to file a 1040-NR.