183-day rule calculator
Use this for any country or US state with a day-count residency rule. Set the threshold (183 is the most common, 184 for NY/NJ/MA/CT, varies elsewhere), configure the tax-year window, and the calculator handles the rest.
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What the 183-day rule actually says
There is no single 183-day rule. There is one number that dozens of unrelated laws happen to share, and each of them defines the count, the period it is measured over, and the consequence differently. The number itself is arithmetic: half of a 365-day year is 182.5 days, so 183 is the smallest whole number of days that is more than half a year. Spend 183 days in one place and you cannot have spent longer anywhere else.
What the number does depends on which of two rules you are reading, and the two are routinely confused:
- Domestic residence tests. A country's own law treats presence for a set number of days inside its own tax year as making you a tax resident, which usually means it can tax your worldwide income and expects a return. This is the rule most people mean, and it is what the calculator above counts against.
- The treaty 183-day rule. Article 15 of the OECD Model Tax Convention, which most bilateral tax treaties are built on, exempts your employment income from tax in the country you are working in only when three conditions hold together: you are present there no more than 183 days in aggregate in the relevant twelve-month period, your employer is not a resident of that country, and your pay is not borne by a permanent establishment your employer has there. Failing any one of the three, not only the day count, hands the taxing right to the country you worked in. Older treaties often measure the 183 days over the fiscal year rather than a rolling twelve months, so read the treaty that actually applies to you.
The two rules are independent. Staying under 183 days in a treaty country can protect your salary while a different domestic test still makes you resident. Where two countries both claim you, the tie-breaker in Article 4 of the same model treaty runs in a fixed order: permanent home, then centre of vital interests, then habitual abode, then nationality, and if none of those settles it, agreement between the two tax authorities. Day counts are the evidence at almost every step.
If both countries have a claim on you, work through the treaty tie-breaker tool next.
Where the number is written down
Four of the most-searched versions of the rule, with the provision each one comes from. Read the wording rather than the number: "at least 183 days" and "more than 183 days" are one day apart, and that day is the whole question.
| Jurisdiction | What the provision says | Basis |
|---|---|---|
| United States | The substantial presence test: 31 days in the current year and 183 days on a three-year weighted count that takes the current year in full, one third of the prior year, and one sixth of the year before that. | 26 U.S.C. § 7701(b)(3) |
| United Kingdom | The first automatic UK test is met if you spend at least 183 days in the UK in the tax year, which runs 6 April to 5 April. A day generally counts if you are in the UK at the end of it. | Finance Act 2013, Schedule 45 |
| Canada | You are deemed resident for the whole year if you sojourned in Canada for periods totalling 183 days or more in the calendar year. Day 183 is enough on its own. | Income Tax Act, section 250(1) |
| New York | Statutory residency requires a permanent place of abode in the state and more than 183 days there in the taxable year, so day 184 is the one that makes you a resident. Any part of a day generally counts as a full day. | N.Y. Tax Law § 605(b)(1)(B) |
Most other jurisdictions are a variation on one of these four patterns: a bare day count, a day count paired with a home you keep available, a weighted count across several years, or a day count that is only one of several tests.
A worked example
Take a 183-day threshold measured over the 2026 calendar year, in a jurisdiction that counts arrival and departure days in full, which is the common case. Four trips:
| Trip | Dates | Days | Running total |
|---|---|---|---|
| 1 | 8 January to 14 February | 38 | 38 |
| 2 | 2 April to 30 June | 90 | 128 |
| 3 | 5 September to 20 October | 46 | 174 |
| 4 | 18 December to 31 December | 14 | 188 |
Every figure counts both end dates. Trip 1 is 38 days, not 37: 24 days in January (the 8th to the 31st) plus 14 in February. Dropping one day per trip is the most common arithmetic error there is, and across a year of frequent travel it hides a week or more.
Trip 4 decides the year. It begins at 174 days, so its ninth day, 26 December, is day 183. The threshold is met, and in most systems that makes the whole year a resident year, including income earned during the eight months spent elsewhere.
Leave on 25 December instead and the year closes at 182 days. One day of calendar separates the two outcomes, which is why the projected crossing date matters more than the running total: it gives you the date to be gone by, before you book the flight.
The 183-day rule, by jurisdiction
Most countries use a 183-day rule for tax residency, but the specifics vary. Here's a quick reference:
- 183 days, calendar year: most countries, Germany, Spain, France, Italy, Mexico, Singapore, Japan, Portugal (12-month rolling).
- 184 days + abode: New York, New Jersey, Massachusetts, Connecticut, Pennsylvania.
- UK SRT (Statutory Residence Test): a tied day-count test on the UK tax year (6 April – 5 April).
- Australia: 183 days on the Australian income year (1 July – 30 June).
- Canada: 183 days deemed-resident rule alongside the residential-ties test.
- UAE: 90 days with residency visa + abode, or 183 days general.
For Schengen 90/180 specifically, use the dedicated Schengen calculator. For the IRS Substantial Presence Test, use the SPT calculator.
The threshold is not always 183
Reaching for a 183-day calculator and then applying 183 to a jurisdiction that uses a different number is a common and expensive mistake. Set the threshold field to your own rule:
- 180 days: Thailand, on the calendar year.
- 182 days: India, on a financial year running 1 April to 31 March, and Malaysia on the calendar year. India also has a second route at 60 days for people with substantial presence over the preceding four years.
- 184 days: New York, and in practice any rule written as "more than 183 days", which includes the statutory-residency tests in New Jersey, Massachusetts, Connecticut and Pennsylvania, each of which also requires a permanent place of abode.
- 200 days: Oregon and Hawaii.
- 270 days: Idaho, alongside a home kept in the state for the whole year.
- About 214 days: Alabama and Oklahoma, whose statutes are written as seven months rather than as a number of days, so the day figure is an approximation and the shorter reading is the safe one.
- No fixed threshold: California, where more than nine months creates a rebuttable presumption of residence while less than nine months creates no presumption the other way, and Illinois, which turns on domicile and purpose rather than on a day count.
- Fewer than 90 days: Cyprus can treat you as resident on 60 days when its other conditions are met in the same year, and the UAE has a 90-day route for specified people with a permanent place of residence and a job or business there.
How a "day" is counted
Most jurisdictions count any presence on a calendar day as a full day. Some require presence at midnight (UK SRT). Some have transit-day exclusions. Read the full guide: The 183-day rule, explained.
The conventions that decide whether a given date lands in your total:
- Any part of a day: New York and several other US states count any presence at all, including a connection between two flights, as a full day. It is the most punitive convention and the one to assume when you do not know which applies.
- Presence at the end of the day: the UK statutory residence test generally counts a day only if you are in the UK at midnight, with limited exceptions for transit and for exceptional circumstances beyond your control, plus a separate deeming rule for people with several UK ties.
- Both ends of the trip: the Schengen 90/180 rule counts the day you enter and the day you leave in full. That is an immigration limit rather than a tax test, and it runs on a rolling 180-day window instead of a year.
- Days that are excluded: the US substantial presence test disregards, among others, days of exempt individuals, days you are in transit between two points outside the United States and are in the country for less than 24 hours, and days you could not leave because of a medical condition that arose while you were there.
- A window that moves: some rules count within any rolling twelve-month period rather than a fixed year, so the window shifts by one day every day and there is no 1 January reset to plan around.
Common mistakes and edge cases
Almost every day-count dispute comes down to one of these:
- Counting nights instead of days. A Friday to Sunday trip is three days under most rules, not two. Repeat that across twenty trips and your count is twenty days light.
- Assuming the year starts on 1 January. The UK tax year runs 6 April to 5 April, Australia's income year 1 July to 30 June, and India's financial year 1 April to 31 March. Set the window before you enter a single trip, or every total is measured over the wrong period.
- Treating the threshold as a safe harbour. Staying under the number is not the same as being non-resident. Domicile, a home kept available to you, where your family lives and where your economic interests sit can each make you resident on far fewer days, and several systems have a deliberate low-day route.
- Forgetting that residence usually covers the whole year. Crossing on 26 December generally makes you resident from 1 January, not from 26 December. Split-year and part-year reliefs exist, UK split-year treatment and the US dual-status year among them, but they are specific reliefs with their own conditions rather than the default outcome.
- Mixing the immigration clock with the tax clock. A 90/180 visitor limit and a 183-day tax test are different rules with different windows and different consequences. Being comfortably inside the 90 days says nothing about your tax position, and a stay that is perfectly legal on immigration can still create a residence question.
- Counting from memory at the end of the year. Tax authorities expect contemporaneous evidence: boarding passes, hotel folios, card transactions. Where the burden of proof sits with you, an undocumented day tends to be counted against you, and reconstructing a year afterwards is usually the moment people discover they were already over.
- Watching only one country. Days out of one place are days in another. Cutting to 150 days somewhere while spending 200 days somewhere else swaps one residence question for a worse one.
If more than one jurisdiction is in play, count them together in the multi-country day counter.
Setting the calculator to your rule
The calculator counts every distinct calendar day inside the window you set, counting entry and exit dates in full and de-duplicating days shared by overlapping trips. To match your rule:
- If your rule says "183 days or more", enter 183. The threshold is reported as met on the day the count reaches it, which is what that wording means.
- If your rule says "more than 183 days", enter 184, the first day that actually makes you resident. The same logic turns any "more than N" rule into a threshold of N plus one.
- Set the window to the jurisdiction's own year, not the calendar year, unless the two are the same.
- Add one row per continuous stay, entry date and exit date. Days covered by two overlapping rows are counted once.
- Enter trips you have not taken yet. The projected crossing date is calculated from everything in the list, so scheduled travel shows you the date you would cross before you commit to it.
Where a rule excludes certain days, transit days under the US substantial presence test for example, leave those days out of the trips you enter rather than expecting the calculator to know about them. It counts calendar days, it does not apply any one jurisdiction's exclusions.
What the 183-day rule does and doesn't do
Is the 183-day rule the same in every country?
No. 183 days in a calendar year is the most common pattern, but the threshold and the window both vary: some US states use 184 days, some countries count 183 days in any rolling 12-month period, and others pair the day count with an abode or domicile requirement. That is why this calculator lets you configure both the threshold and the window.
Do arrival and departure days count toward the total?
It depends on the jurisdiction. Many treat any part of a day as a full day, others count midnights, and some make exceptions for transit. When in doubt, count conservatively (both days in) and keep a day-by-day record.
If I stay under 183 days, am I safe from tax residency?
Not necessarily. Day counts are only one trigger: domicile, a permanent home, family and economic ties, or a treaty tie-breaker can make you a resident with far fewer days. Staying under the threshold helps, but it is not a guarantee.
Which tax-year window should I use?
Most countries measure over the calendar year. The UK uses 6 April to 5 April, Australia 1 July to 30 June, and a few jurisdictions use a rolling 12-month window. Set the window to match your jurisdiction before adding trips, our tax year calculator shows the dates for common jurisdictions.
What happens if I cross the threshold?
Generally the jurisdiction can treat you as a tax resident for that year, which often means local tax on worldwide income and new filing obligations. Exceptions, treaty relief, and part-year rules vary, so confirm the consequences with a professional before relying on them.
Does this calculator store my trips?
No. Everything runs in your browser. For continuous tracking with projections and alerts, the Tax Days iPhone app stores trips privately on your device.
How do I calculate 183 days?
Count every calendar day you were physically present in the jurisdiction during its own tax year, including the day you arrived and the day you left unless the rule says otherwise, then compare the total against the threshold. Worked through: 8 January to 14 February is 38 days, 2 April to 30 June is 90, 5 September to 20 October is 46 and 18 December to 31 December is 14, which totals 188 days and crosses a 183-day threshold on 26 December.
Is the rule 183 days or more, or more than 183 days?
It depends on the provision, and the two readings are one day apart. Canada's Income Tax Act deems you resident at 183 days or more, and the UK's first automatic test is met at at least 183 days, so day 183 is decisive in both. New York's statutory-residency test uses more than 183 days, which is why the New York figure is usually quoted as 184. Set the calculator's threshold to the first day that counts against you.
Does the 183-day rule apply to US citizens?
No. The United States taxes its citizens and lawful permanent residents on worldwide income wherever they live and however few days they spend there, so no day count makes a US citizen a federal non-resident. Day counts still matter to Americans abroad for the 330-day physical presence test behind the foreign earned income exclusion, which has its own 330-day calculator, and for US state residency, where a state such as New York or California can still treat you as a resident.
Is 183 days the same as six months?
Not exactly. Six consecutive calendar months run from 181 to 184 days depending on which six they are, so a rule written in months and a rule written in days do not resolve to the same date. That is precisely why most tax law uses days. See 183 days in months for the conversion.
What is the 183-day rule in a tax treaty?
It is a different rule from the residence test and it concerns employment income only. Article 15 of the OECD Model Tax Convention, which most bilateral treaties follow, allows the country you are working in to tax your salary unless three conditions all hold: you are present there no more than 183 days in the relevant twelve-month period, your employer is not a resident of that country, and your pay is not borne by a permanent establishment there. Meeting them protects the salary, not your residence status.
Can I be a tax resident with fewer than 183 days?
Yes, and this is where counting days alone catches people out. Domicile, keeping a home available, where your family lives and where your economic centre sits can all make you resident on far fewer days. Cyprus can treat you as resident on 60 days when its other conditions are met, the UAE has a 90-day route for specified people with a home and a job or business there, and states such as California apply a facts-and-circumstances test with no fixed threshold at all.
Do days spent in transit count?
It varies, and you cannot assume the generous answer. New York counts any part of a day in the state, including an airport connection. The US substantial presence test disregards days when you are in transit between two points outside the United States and are in the country for less than 24 hours. The UK generally counts a day if you are there at the end of it, with limited transit exceptions. Count conservatively and keep the boarding passes.
Does this calculator work for the Schengen 90/180 rule?
No. Schengen counts over a rolling 180-day window rather than a fixed year, so it needs different arithmetic. Use the Schengen calculator for that, and keep in mind that it is an immigration limit rather than a tax test.
Sources & further reading
Every rule on this page is drawn from primary sources. Verify the current law before making a residency decision.
- [1]OECD Model Tax Convention, Article 4 (Resident) tie-breaker (opens in a new tab)OECD
- [2]26 U.S.C. § 7701(b), definition of resident alien and the substantial presence test (opens in a new tab)Office of the Law Revision Counsel
- [3]Substantial Presence Test (opens in a new tab)IRS
- [4]Finance Act 2013, Schedule 45, the statutory residence test (opens in a new tab)legislation.gov.uk
- [5]Income Tax Act, section 250(1), person deemed resident (sojourning 183 days or more) (opens in a new tab)Justice Laws Website, Canada
- [6]NY Tax Law § 605 (resident definition) (opens in a new tab)NY Senate
Track every jurisdiction at once
Tax Days tracks 80+ residency rules across 254 jurisdictions on your iPhone. Add a trip once and the app updates every applicable rule simultaneously.
