Am I a US Resident for Tax Purposes? Substantial Presence Test
The 183-day formula isn't what you think. Here's the exact IRS Substantial Presence Test calculation, the exempt-individual rules, and a worked example.
Sneha Rao
Updated May 23, 2026 · 8 min read
Whether you're taxed by the US on your worldwide income or only your US income hinges on a single question: are you a US resident for tax purposes? This has nothing to do with your green card or visa type — it's decided by a day-counting formula called the Substantial Presence Test (SPT). Get it wrong and you'll either overpay, underpay, or trip into the dreaded "dual-status" year. Here's exactly how the SPT works, with the exceptions that catch students and a worked example.
In a nutshell
You're a US resident for tax purposes if you meet the Substantial Presence Test: present at least 31 days this year AND 183 days across a 3-year weighted formula (all days this year + ⅓ of last year + ⅙ of the year before). F-1 students (5 years) and J visa holders (2 years) are "exempt individuals" whose days don't count. Residents are taxed on worldwide income; nonresidents only on US income.
Key takeaways
- The SPT decides whether you're taxed on worldwide or only US income.
- Formula: 31+ days this year AND 183 weighted days over three years.
- Weighting: 100% of this year's days + ⅓ of last year + ⅙ of two years ago.
- F-1 students are exempt for 5 calendar years; J-1 holders for 2 — their days don't count.
- Your first year on H-1B is often dual-status (part nonresident, part resident).
- Meeting the SPT triggers FBAR/FATCA and worldwide-income reporting.
Why this is the most important tax question for newcomers
Your residency status determines the entire shape of your US tax return. Resident aliens are taxed like US citizens — on income from everywhere, including India — and must file FBAR/FATCA. Nonresident aliens are taxed only on US-source income and file Form 1040-NR. Misjudging this leads to wrong filings and penalties, so nail it first.
The Substantial Presence Test, step by step
You're a resident for the current year if both are true:
- You were present in the US at least 31 days during the current year, and
- You were present at least 183 days over the three-year period, counting:
- All the days you were present this year, plus
- ⅓ of the days you were present last year, plus
- ⅙ of the days you were present the year before that.
A worked example
Say you were in the US for 150 days in 2026, 120 days in 2025, and 120 days in 2024:
| Year | Days present | Weight | Counted days |
|---|---|---|---|
| 2026 | 150 | × 1 | 150 |
| 2025 | 120 | × ⅓ | 40 |
| 2024 | 120 | × ⅙ | 20 |
| Total | 210 |
You were present 31+ days in 2026 and your weighted total is 210 ≥ 183, so you meet the SPT and are a resident for tax purposes in 2026.
The exempt-individual exceptions
Some people don't count their days at all, for a limited time:
- F-1 students: exempt individuals for their first 5 calendar years in the US — their days don't count toward the SPT, so they file as nonresidents during that window.
- J-1 scholars/researchers: generally exempt for 2 years.
This is why a PhD student can be in the US for years and still file as a nonresident — until the exemption runs out, after which the day-count begins to apply.
The dual-status first year. Many H-1B holders arriving mid-year are dual-status: nonresident for the part of the year before they met the SPT, resident afterward. Dual-status returns are fiddly (you can't use the standard deduction the usual way, etc.), which is why year one often warrants a CPA. See our first US tax return guide.
Other wrinkles worth knowing
- First-Year Choice and closer-connection exceptions can alter your status in specific cases.
- Days you're in the US as an exempt individual or unable to leave due to a medical condition may not count.
- Becoming a resident triggers worldwide income reporting — including Indian income — with DTAA relief to avoid double tax.
Frequently asked questions
How many days make me a US tax resident?
You need 31+ days in the current year and a weighted total of 183 days over three years (this year + ⅓ of last year + ⅙ of the year before). Meeting both makes you a resident.
Do F-1 student days count toward the test?
No. F-1 students are exempt individuals for their first 5 calendar years, so their days don't count and they file as nonresidents during that period.
What is a dual-status year?
A year in which you're a nonresident for part of it and a resident for the rest — common in your first H-1B year. The two periods are taxed under different rules.
Does meeting the test mean I report my Indian income?
Yes. Once you're a resident for tax purposes, you report worldwide income, including Indian income, with foreign tax credits to prevent double taxation.
The bottom line
The Substantial Presence Test, not your visa, decides whether the US taxes your worldwide income. Count this year's days fully, last year's at a third, and the year before at a sixth — clear 183 (and 31 this year) and you're a resident. Remember the 5-year F-1 and 2-year J-1 exemptions, watch for a dual-status first year, and once you're a resident, get your worldwide income and FBAR reporting right.