Why day counting is harder than it looks
Every rule on this site reduces to the same question — how many days were you in a place? — and every one of them answers it differently. The differences are small enough to look like details and large enough to change the outcome.
- Which days count. Schengen counts both your arrival and departure days in full. The UK counts a day only if you were present at midnight, so the departure day does not count at all. Apply the wrong convention and every trip is off by one.
- Over what period. Some rules use a calendar year, some a tax year starting in April or July, and some a rolling window with no reset date at all. A rolling window is the one people misjudge, because there is no date to plan around.
- How days are weighted. The US Substantial Presence Test counts this year's days in full, last year's at a third, and the year before at a sixth. You can become a US tax resident on 122 days.
- What the threshold actually decides. Immigration limits and tax residency thresholds are unrelated. Someone doing three lawful 60-day stays in Thailand never comes close to an overstay and lands exactly on the 180-day tax residency line.
Which calculator do you need?
Travelling in Europe on a passport that does not need a visa? The Schengen 90/180 calculator tells you how much of your allowance is left and the earliest date you can return.
Spending significant time in the United States? The Substantial Presence Test calculator shows the weighted three-year arithmetic line by line, handles exempt individuals, and flags when the Closer Connection Exception may apply.
Coming to or leaving the UK? The Statutory Residence Test counter uses the real 6 April tax year and the midnight rule, then applies the arriver and leaver ties bands.
Moving between several countries? The tax residency day tracker takes one trip log and checks it against thresholds in more than twenty countries at once, each with its own period and counting rule.
Long stays in Asia? The Thailand and Japan counters track per-entry allowances alongside the cumulative totals that attract immigration attention.
How these tools work
Everything is computed in your browser. There is no account, no server, and no database — your trip dates are stored in your own browser's local storage so they are still there when you come back, and nothing is transmitted to us. You can export any trip log to CSV or copy a plain-text summary at any time.
The date arithmetic is deliberately timezone-free: dates are handled as calendar days rather than timestamps, so daylight saving transitions cannot shift a count by a day. Every rule is covered by an automated test suite, because the entire value of a calculator like this is that the number is right.