The 183-day rule: how the days are counted

Many countries treat spending 183 or more days there in a year as a sign that you are resident for tax. Many tax treaties use the same threshold to decide which country may tax your salary. But there is no single 183-day rule: each country decides what year it counts, which days count, and whether 183 is decisive or only one factor among several.

Crossing 183 days does not automatically make you tax resident anywhere, and staying under it does not automatically make you not. What the number reliably does is make the question live — which is why the count is worth keeping, and worth keeping accurately.

It is the smallest whole number of days that is more than half of a 365-day year: spend that many days somewhere and you spent most of the year there. As a rule of thumb about where someone lives, it is hard to argue with, and tax systems adopted it as a bright line because it is easy to test.

The OECD Model Tax Convention, the template most bilateral tax treaties follow, uses it in its article on employment income: pay for work done in a country generally stays taxable only at home if, among other conditions, you are present in the other country for no more than 183 days in any twelve-month period. That is a rule about which country taxes a salary. Residence is a separate article, decided by permanent home, centre of vital interests, habitual abode and nationality, in that order — not by a day count.

The same number is defined differently everywhere it appears, and the differences decide the answer:

• The period. Some countries count a calendar year. Some count a tax year that starts elsewhere — the United Kingdom’s runs from 6 April. Some count any rolling twelve months. The United States weights three years together: all of this year’s days, a third of last year’s and a sixth of the year before.
• The day. Some count any day on which you were present at all; the United Kingdom counts the days you were there at midnight; some exclude days in transit or days spent in the country because of illness.
• The weight. In some places 183 days is conclusive. In others it is one test among several, and you can be resident with far fewer days because of a home, a family or a business there.
• The tie-break. When two countries both claim you, a treaty decides — usually by permanent home first, then centre of vital interests, then habitual abode — and the day count is at most an input to the third.

None of this is something a day count can settle. All of it is something a day count is asked about.

Whatever the definition, the tally itself follows a few habits worth adopting:

• Count in days, not months. Three months is 89 to 92 days, and the difference is exactly the margin these rules turn on.
• Count the day you arrive and the day you leave. Some tests do and some do not; counting both gives you the cautious figure, and it is far easier to subtract two days later than to find them.
• Count every stay in the period and add them up. A rule that counts a year counts the whole year, not the longest trip in it.
• Write down the dates as they happen. A test that asks where you were at midnight on a given Tuesday is not one you can answer from memory in eighteen months’ time.

Take a country that counts days in a calendar year, and a year with three stays in it: 10 January to 20 February, 1 May to 15 July, and 3 September to 10 October. Counting both ends of each, the stays are 42, 76 and 38 days — 156 in the year, and 27 short of 183.

Now add a fortnight in December, 1 to 14 December: 170. Add a second fortnight straight after it, 15 to 31 December, and the year ends on 187 — over the line by four days, fewer than the number of arrival and departure days in the year, which a different test might not have counted at all.

Run the same trips against a tax year that starts in April instead, and the January and February stay drops out of the window entirely while the December ones stay in. Same trips, same traveller, a different year, a different answer. Neither answer says anything about where you are resident on its own; each is the number the question starts from.

The rule is misquoted more often than it is quoted:

• “Over 183 days and you are tax resident.” Often a strong sign, never the whole test. Treaties, other domestic tests and your circumstances decide.
• “Under 183 days and you are safe.” Not where a home, a family or a business ties you to the place, and not where a lower day threshold applies alongside those ties.
• “The year is January to December.” Only where it is. Check which year the country you are counting for uses.
• “Arrival and departure days are half days.” Under some tests they are whole days, under some they do not count at all. There are no half days; there are only definitions.
• “Working remotely doesn’t count.” Presence is presence. What you were doing on the day rarely changes whether you were there.

When a tax authority asks where you were, the burden of showing it is on you, and the question tends to arrive years after the year in question. Boarding passes are discarded, stamps fade, and email confirmations describe what was booked rather than what happened.

A record kept at the time — the date you arrived, the date you left, for every country — answers the question in one table. It also lets you see the number coming: the point of counting is to make decisions before the year ends, not to reconstruct it afterwards.

DaysHere counts days per country from the entry and exit dates you log. A calendar-year rule counts them against a yearly ceiling — 183, or whatever figure you choose — and a custom rule counts against your own limit over your own period. Each country shows the days you have used, the days you have left and the day you would reach the line, with a reminder before you do.

The app counts both the arrival day and the departure day as days of stay. If the test you are counting for does not, its figure will be slightly below the app’s, which is the safe direction to be wrong in.

DaysHere does not know your tax position and does not decide it. It keeps the tally that every version of the question begins with, and lets you export the whole history as a CSV when someone asks to see it.

How the UK counts a visit, and why that is different again

This page describes how day counts work in general. It is not tax advice, it does not describe the law of any particular country, and it cannot tell you where you are resident. The rules differ by country and change; for your own situation, read the rules of the countries concerned and speak to a professional who knows them.