Why this exists
If you live between countries, a surprising amount of your legal position comes down to arithmetic on a set of dates. How many days in Schengen in the last 180. How many in the US across three years, weighted. How many in the UK between one 6 April and the next, counted at midnight.
The arithmetic is not hard, but it is fiddly and unforgiving, and it is easy to get wrong in ways that are invisible until a border officer or a tax authority points them out. Most people do it in a spreadsheet, and most spreadsheets get at least one convention wrong — usually whether the departure day counts.
These tools do the counting properly and show their working.
How they are built
Everything runs in your browser. There is no account, no server-side processing and no database. Your trip dates are stored in your own browser's local storage so they persist between visits, and they are never transmitted to us. See the privacy policy for detail.
Dates are handled as calendar days rather than timestamps. That sounds like an implementation detail, but it is the reason these counters do not drift: a timestamp-based calculation can shift by a day across a daylight saving transition, and several published calculators do exactly that. Here, the difference between two dates is integer subtraction and cannot round the wrong way.
Every rule is covered by an automated test suite that runs on each change, including the boundary cases where these rules actually bite — the 180th day versus the 181st, the leap-year stay, the trip that straddles 6 April. The whole value of a calculator is that the number is right.
The counting conventions
Different rules count differently, and applying one convention everywhere is the most common source of error:
- Schengen, Thailand, Japan and most tax rules count any part of a day of presence as a full day, so both arrival and departure days count.
- The UK counts a day only if you were present at midnight, so the departure day does not count.
- The US Substantial Presence Test weights three years: the current year in full, the prior year at one third, the year before at one sixth.
Where we say "we don't know"
Several of these rules have genuinely unsettled areas — the status of Schengen bilateral agreements, what counts as available accommodation under the UK test, whether remote work is permitted on a visitor stamp. Where that is the case, the pages say so rather than inventing certainty.
A calculator that gives a confident answer to an ambiguous question is worse than no calculator, because you cannot tell which of its answers to trust.
What is here
- Schengen 90/180 Calculator — How many of your 90 days in any rolling 180 are left, and when you can next enter.
- US Substantial Presence Test Calculator — Whether your US days make you a tax resident, with the 1 + 1/3 + 1/6 weighting shown in full.
- UK Statutory Residence Test Calculator — Automatic tests plus the sufficient ties bands, counted on the real 6 April tax year.
- Tax Residency Day Tracker — One trip log, checked against every country threshold at the same time.
- Thailand Visa Run Planner — Entry-stamp counting for visa exemption stays, extensions and border runs.
- Japan 90-Day Calculator — Visa-free stay tracking across repeat entries, with re-entry guidance.
Corrections
Rules change and mistakes happen. If you find an error — in a threshold, a date boundary, or an explanation — please report it via the contact page. Corrections are acted on, and they are the most useful message you can send.
How the site is funded
The calculators are free and will stay free. The site is supported by advertising and by affiliate links, which appear only in clearly labelled blocks that are kept visually separate from calculator results. A commercial relationship never affects a number this site produces. See the disclaimer for the full position.