To determine whether you should use Form 1040-NR or Form 1040, the key factor is your tax residency status in the United States:

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✅ Use Form 1040 if you are a U.S. tax resident.

This includes:

• U.S. citizens

• Green card holders (Lawful Permanent Residents)

• Resident aliens (non-citizens who meet the Substantial Presence Test)

✅ Use Form 1040-NR if you are a nonresident alien for tax purposes.

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🔍 How to determine your tax residency status:

✔ Green Card Test:

• If you had a green card (U.S. lawful permanent resident status) at any time during the tax year, you are a resident alien for tax purposes.

✔ Substantial Presence Test:

You’re generally considered a resident alien if you were physically present in the U.S. for:

• 31 days during the current year, and

• 183 days during the 3-year period that includes the current year and the two years immediately before, calculated as:

  • All the days you were present this year

  • 1/3 of the days you were present last year

  • 1/6 of the days you were present two years ago

If you do not meet either of these tests, you are likely a nonresident alien and should file Form 1040-NR.

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🧠 Example Scenarios:

Situation	Use Form
F-1 student in the U.S. less than 5 years	1040-NR
H-1B worker in the U.S. for over 183 days this year	1040
Green card holder	1040
Visiting professor on J-1 visa, 2nd year in U.S.	Likely 1040-NR (exempt from SPT for 2 years)