How to track your days in a country for tax
Count every day you were physically present in a country at midnight, against that country's own tax year rather than the calendar year, and keep evidence you did not have to remember to create — passport stamps, boarding passes, card transactions. Most people get caught out by three things: arrival and departure days usually both count as full days, tax years do not all start in January, and a count reconstructed at the end of the year is almost always wrong.
Most countries decide whether you are a tax resident by counting days. It sounds like the simplest possible test, which is why so many people get it wrong — the counting rules are more particular than they look, and the record almost never exists when it is needed.
Why does the day count matter so much?
Tax residency is what determines which country can tax you, and often on what. Cross a threshold and a country may be able to tax your worldwide income rather than just what you earned locally. Stay below it and you may owe nothing there at all.
The threshold is usually 183 days, though not always — the 183-day rule is a widespread convention rather than a standard, and Thailand’s is 180. Either way, the consequence turns on a number you are expected to be able to produce.
What actually counts as a day?
The common test is physical presence at midnight: if you were in the country when the date changed, that day counts as a full day. Not a half day, not a partial day, and usually with no regard for how many hours you were there.
Two consequences catch people out:
- Arrival and departure days often both count. Fly in on Friday evening and out on Monday morning and you have used three days, not two.
- Short trips add up faster than expected. Twelve weekend trips a year is not twenty-four days, it is thirty-six.
Some countries exclude days in transit, or days you could not leave for medical reasons. Those exemptions tend to be narrow and to require evidence, so treat them as a defence rather than a plan.
Which year do the days count against?
Against that country’s tax year — and tax years do not agree with each other.
| Country | Tax year |
|---|---|
| Thailand, most of Europe | 1 January – 31 December |
| United Kingdom | 6 April – 5 April |
| Australia | 1 July – 30 June |
| United States | Calendar year, but days are weighted across three years |
If you are counting towards a UK threshold using a calendar year, your number is simply wrong. This is a common and entirely avoidable error.
What evidence actually holds up?
The standard you want is a contemporaneous record — something created at the time, not reconstructed afterwards from memory.
Passport stamps used to be the obvious answer. They are less reliable now that so many borders are automated and stamp nothing at all, which leaves a lot of people with no formal record of their own movements. What fills the gap:
- Boarding passes and flight confirmations
- Hotel and accommodation bookings
- Dated card transactions in the country
- Immigration records, where the country lets you request them
None of these is individually conclusive. Together they corroborate each other, which is generally what matters.
How do you keep the count without it becoming a chore?
Honestly: manual tracking fails, and it fails predictably.
A spreadsheet works beautifully for one trip. Across a year of movement it decays, because it depends on you remembering to update it on exactly the days you are least likely to — travel days, when you are in an airport, tired, and thinking about anything else. By December you are reconstructing from memory, which is both laborious and the weakest kind of evidence.
The approach that survives contact with real life is to derive the count from something you already do every day without being reminded. You spend money daily, and the currency you spend says where you were.
That is how Stays works in Stang: your ordinary expense log doubles as a day count per country, with no GPS and no check-ins. Buy lunch in baht and the day counts towards Thailand. Because the record is a side effect of something you were doing anyway, it is still there in December.
It will not replace formal evidence if you are close to a threshold and need to defend a position. What it gives you is knowing where you stand during the year, while you can still change the outcome.
This is general information, not tax advice. Residency rules are specific to each country and to your circumstances. If you are near a threshold, or you might be resident in two countries at once, speak to a tax professional familiar with both.
