Why this question matters so much
Before you can file a U.S. tax return, you need to know one thing: are you a resident alien or a nonresident alien for tax purposes?
This single determination affects everything else:
- Which tax form you file (Form 1040 vs. Form 1040-NR)
- What income you must report (worldwide vs. U.S.-source only)
- Whether you can claim the standard deduction
- Which tax credits you can access
- Whether you can file jointly with a spouse
Getting this wrong — especially filing as a resident when you should be a nonresident, or vice versa — is one of the most consequential errors a new immigrant can make. It affects every other part of your return.
These are completely separate concepts. You can be a legal permanent resident (green card holder) for immigration purposes and still be treated differently for tax purposes in your first year. Conversely, you can be on a temporary visa and be a full resident alien for tax purposes. The IRS makes its own determination based on physical presence and status — not your visa type.
The two tests — and which applies to you
The IRS uses two tests to determine if you are a resident alien. If you meet either test, you are a resident alien.
Test 1: The Green Card Test
Simple: if you were a lawful permanent resident (green card holder) at any time during the tax year, you are a resident alien for that entire year.
There are no day-count calculations. No exceptions based on where you lived. If you held a green card, you're in — for the entire year, even if you got it on December 30th.
Test 2: The Substantial Presence Test
If you don't have a green card, the IRS counts how many days you were physically in the U.S. over a three-year period using this formula:
If both conditions are met → you are a resident alien for the current year.
A worked example
Let's say you arrived on an H-1B visa and were present in the U.S. as follows:
| Year | Days present | Multiplier | Weighted days |
|---|---|---|---|
| Current year (2025) | 210 days | × 1 | 210 |
| Prior year (2024) | 180 days | × 1/3 | 60 |
| Year before (2023) | 120 days | × 1/6 | 20 |
| Total | 290 ≥ 183 ✓ | ||
Result: Resident alien for 2025. Files Form 1040, reports worldwide income.
Exempt individuals — days that don't count
Not all days in the U.S. count toward the Substantial Presence Test. If you are an "exempt individual," your days in the U.S. during that status are excluded from the count.
| Visa type | Exempt period | Notes |
|---|---|---|
| F-1 student | First 5 calendar years in F-1 status | After year 5, days start counting normally |
| J-1 student | First 5 calendar years in J-1 status | Same as F-1 |
| J-1 non-student (teacher, researcher) | First 2 calendar years in J-1 status | Shorter exemption period |
| Diplomat / government official (A or G visa) | Entire period of official status | Full exemption while on official assignment |
| Medical condition | Days unable to leave due to medical emergency | Must have intended to leave; file Form 8843 |
Being an exempt individual means your days don't count toward the Substantial Presence Test. It does NOT mean you're exempt from paying U.S. taxes. Nonresident aliens still owe U.S. tax on U.S.-source income and must file Form 1040-NR if they have U.S. income above the filing threshold.
Quick determination flowchart
What each status means for your taxes
| Topic | Resident alien | Nonresident alien |
|---|---|---|
| Tax form | Form 1040 | Form 1040-NR |
| Income taxed | Worldwide income | U.S.-source income only |
| Standard deduction | Yes ($15,000 single in 2025) | No (itemize only) |
| Joint filing with spouse | Yes | Generally no (unless election made) |
| Most tax credits | Yes (Child Tax Credit, EITC, etc.) | Limited (some credits not available) |
| Tax treaties | May still apply | May reduce or eliminate U.S. tax on certain income |
| FBAR requirement | Yes (if foreign accounts > $10,000) | Yes (if foreign accounts > $10,000) |
Special situations
The "closer connection" exception
If you pass the Substantial Presence Test but were present fewer than 183 days in the current year, you may still be treated as a nonresident alien if you can show a "closer connection" to a foreign country. You prove this by filing Form 8840 and demonstrating that your primary home, family, bank accounts, and other ties are in another country. This exception is not available if you have applied for a green card.
The first-year choice election
If you arrive in the U.S. and don't quite meet the Substantial Presence Test in your first year, but you do meet it the following year, you may be able to elect to be treated as a resident alien for the last part of your first year. This is called the "first-year choice" election and requires meeting specific conditions. It can simplify your filing situation and unlock additional deductions.
Dual-status year
In the year you become a U.S. tax resident (or the year you leave), you may be a nonresident for part of the year and a resident for the rest. This is called a "dual-status" year and requires a more complex return — generally a Form 1040 with a 1040-NR attachment. Dual-status filers cannot use the standard deduction or file jointly. Professional help is strongly recommended for dual-status returns.
If any of these apply to you, consult a CPA before filing: your year of arrival or departure, dual-status year, you qualify for a closer connection exception, you want to make a first-year choice election, or your spouse has a different residency status. These situations involve elections that are difficult or impossible to undo after filing.