Have your days made you a U.S. tax resident?
The United States counts three years of your travel, not one, and weights them. People cross the line without moving anywhere. Run your own numbers below.
counted in full
one third counts
one sixth counts
Enter the number of days you were physically present in the United States in each year. Part days generally count as full days.
A non-resident is taxed by the United States only on U.S.-source income. A resident is taxed on income from everywhere in the world, and has to report foreign bank accounts and foreign assets as well.
Nothing about your visa, your home, or your intentions changes that on its own. For someone who is not a citizen or green card holder, it comes down to arithmetic on days.
Which is also the good news: it is measurable in advance, and it can be planned around before the year closes rather than argued about afterwards.
Two conditions, both of which have to hold.
The second one is where the surprise lives. Most people know about 183 days. Very few know that the previous two years are counted too.
- Condition one
You were physically present in the United States on at least 31 days during the current year. Fail this and the test is not met, no matter what the second condition produces.
- Condition two
Your days across three years reach 183 when weighted: all of this year's days, plus one third of last year's, plus one sixth of the year before that's.
Worked example120 days this year = 120.00150 days last year ÷ 3 = 50.00150 days two years ago ÷ 6 = 25.00Total = 195.00 → the day count is metFour months a year, three years running, and you are over the line. Nobody in that example moved to the United States.
The count is not just a count.
Several categories of day are excluded outright. This is the first place to look if the calculator gave you a number you did not want.
Days you were an exempt individual
Certain people do not count their days at all, for a limited number of years. Students on F, J, M or Q visas, teachers and trainees on J or Q visas, foreign government-related individuals, and professional athletes competing in charitable events. The exemption is not permanent and the year limits differ by category, which is where people are caught out.
Days you could not leave because of a medical condition
If a medical condition that arose while you were in the United States stopped you leaving, those days can be excluded. It has to have arisen while you were here. A pre-existing condition you travelled with does not qualify.
Days commuting from Canada or Mexico
If you regularly commute to work in the United States from a home in Canada or Mexico, those commuting days do not count. Regularly means more than 75% of your workdays in the period.
Days in transit
Less than 24 hours in the United States while travelling between two other countries does not count, provided you do not attend a business meeting or otherwise engage while here.
Days as a crew member
Days as a regular crew member of a foreign vessel travelling between the United States and another country do not count, unless you otherwise engaged in a trade or business in the United States that day.
Meeting the test is not always the end of it.
Each of these is a position you claim and file. None of them happens automatically, and each can be lost by being claimed late.
The closer connection exception
Even when the arithmetic says you meet the test, you may be able to stay a non-resident if you were present fewer than 183 days in the current year, kept a tax home in another country for the whole year, and had a closer connection to that country than to the United States. Closer connection is judged on where your home, family, belongings, bank, driving licence, voter registration and social ties are. It is claimed by filing Form 8840, and it is not available if you have applied for, or taken steps towards, a green card.
A treaty tie-breaker
If you are resident in a country with a U.S. income tax treaty and you are treated as resident in both countries under their domestic rules, the treaty has a tie-breaker that decides which country wins. It works through a sequence: permanent home, then centre of vital interests, then habitual abode, then nationality. Relying on it is a filing position you take and disclose, not something that happens automatically.
First-year choice and dual-status years
The year you arrive or leave is often split, with part of it taxed as a non-resident and part as a resident. There is also an election that can let you be treated as a resident earlier than the test would otherwise allow, which is occasionally worth making. These interact with each other and with the treaty, and the right answer depends on the numbers.
121 days a year, indefinitely.
This is the number worth knowing if you travel to the United States on a regular pattern rather than for one unusual year.
If you spend the same number of days in the United States every year, the weighting collapses into a single multiplier. All of this year, a third of last year and a sixth of the year before is 1 + ⅓ + ⅙ = 1.5. So a steady pattern of D days a year produces a weighted total of 1.5 × D.
Two cautions before anyone treats that as a rule. It only holds if the pattern is genuinely steady, because one heavy year distorts the following two. And it is the day count only, which is not the same thing as your tax position: a green card makes you a resident at any day count, and exempt-day status can put you outside the test entirely.
Residency changes more than your own return.
This is the part that general residency guides leave out, and it is where the real cost usually sits.
Your LLC's reporting position can change
The annual Form 5472 obligation on a single-member LLC exists because the owner is a foreign person. If you become a U.S. tax resident, the ownership is no longer foreign, and what the entity has to file changes with it. That cuts both ways and it is not automatically an improvement.
Your treaty position may fall away
Treaty benefits generally depend on being resident in the other country. If the day count makes you resident in both, the tie-breaker decides which country wins, and losing it can remove the reduced withholding rate you have been relying on.
Foreign company and account reporting switches on
A U.S. tax resident who owns companies outside the United States picks up a set of annual information returns about those companies, alongside FBAR and foreign asset reporting. These carry their own penalties, and they are frequently missed in the first year precisely because nothing about the business changed.
Permanent establishment is a separate question
Whether your business has a taxable presence in the United States is decided on where its people, property and agents are, not on your personal day count. You can be a non-resident with a business that is fully taxable here, and a resident with a business that is not.
Asked most often.
More on scope, filings and how the firm works is on the questions page.
What is the substantial presence test?
The substantial presence test is how the United States decides whether someone who is not a citizen or green card holder has been present enough to be taxed as a U.S. resident. You meet it if you were physically present at least 31 days in the current year, and 183 days or more counting all the days in the current year, one third of the days in the previous year, and one sixth of the days in the year before that.
How do I calculate the 183 days?
Add every day you were present in the current year, plus one third of your days in the previous year, plus one sixth of your days in the year before that. If the total is 183 or more, and you were present at least 31 days in the current year, you meet the test. For example, 120 days in each of three years gives 120 + 40 + 20 = 180, which is just under the threshold.
Does a part day count as a full day?
Yes. Any day on which you were physically present in the United States at any time generally counts as a full day, including the day you arrive and the day you leave.
What happens if I meet the substantial presence test?
You are treated as a U.S. tax resident for that year, which means you are taxed on your worldwide income rather than only on U.S.-source income, and you pick up foreign account and asset reporting obligations such as FBAR and Form 8938. You would generally file Form 1040 rather than Form 1040-NR. This is why the test matters far more than the number of days suggests.
Can I avoid becoming a U.S. tax resident if I pass the day count?
Sometimes. If you were present fewer than 183 days in the current year, kept a tax home abroad and had a closer connection to that country, you may claim the closer connection exception on Form 8840. If your country has a U.S. tax treaty, the treaty tie-breaker may also resolve residency in favour of that country. Both are positions you have to claim, with a filing, and both can be lost by claiming them late or not at all.
Do days on a student or J-1 visa count?
Often not, for a limited period. Students on F, J, M or Q visas and teachers or trainees on J or Q visas are treated as exempt individuals whose days do not count, but only for a set number of years that differs by category. Once that period runs out the days start counting, and the change frequently goes unnoticed.
Does the green card test work the same way?
No. It is a separate test. If you are a lawful permanent resident at any point in the year you are a U.S. tax resident regardless of how many days you spent in the country. The substantial presence test only matters for people who are not green card holders.
I think I already met the test in a past year. What should I do?
Have someone work out which years were affected and what was actually required for each, before anything is filed. There are established procedures for coming into compliance and which one fits depends on the facts, including whether the failure was wilful. It is a solvable position and it is better addressed before the IRS raises it.
If the number came out badly, it is worth a conversation.
Residency is one of the few things in tax that can genuinely be planned around, but only before the year closes. Ali Gulzari is a Certified Public Accountant and IRS Enrolled Agent who works on exactly this.
The material on this site is general information about U.S. and cross-border tax mechanics. It is not tax, legal, accounting, or investment advice, it is not written to be relied upon by any particular taxpayer, and it does not create a professional relationship. Engage the firm in writing before acting on anything here. The calculator on this page runs in your browser and sends nothing anywhere. It applies the day count only; it does not apply exempt-day rules, the closer connection exception, or any treaty.