Trip Duration Calculator

What this tool does

The Trip Duration Calculator works out how long a journey really takes when its start and end are in different time zones. You enter the departure date, time and time zone, then the arrival date, time and time zone, and the tool converts both to the same absolute moment before subtracting. The result is the genuine elapsed travel time — shown in hours and minutes and also as a fraction of a day — alongside the misleading “clock-time” difference and the time-zone gap that explains why the two figures differ.

When you’d use it

The classic case is a flight. Your ticket shows a departure time and an arrival time, both in local clocks, and the gap between them is almost never the real duration. Travellers use this tool to know how long they will actually be in transit — how long a flight, layover and onward leg add up to, how much of a day a long-haul trip will consume, or whether a “short” hop across several time zones is really as short as it looks. It is equally handy for comparing two routings, for planning when to sleep on a long flight, and for setting expectations before a big journey.

How to use it

1. Under Departure, enter the date and time you leave, then choose the time zone of your departure city.
2. Under Arrival, enter the date and time you land, then choose the time zone of your arrival city.
3. Read the actual travel time at the top of the result — this accounts for the time-zone difference.
4. Compare it with the clock-time difference and the time-zone gap shown below to see exactly why the ticket times can be deceptive.
5. Use the copy button to save the duration.

How it works

Every wall-clock time belongs to a time zone, and a time zone is defined by its offset from Coordinated Universal Time (UTC). The calculator takes your departure date and time, applies the departure zone’s offset, and turns it into an absolute UTC instant. It does the same for the arrival. Subtracting one absolute instant from the other gives the true elapsed time, free of any time-zone illusion. The “clock-time difference” shown alongside is what you would get by naively subtracting the two local times — useful only to illustrate how far off that shortcut can be. The time-zone gap is the difference between the two offsets, and it is precisely the amount by which the naive figure is wrong.

Tips

Always use the local times printed on your itinerary — airlines, rail operators and bus companies quote departure and arrival in each location’s own local clock, which is exactly what this tool expects. Watch out for daylight saving: a city’s offset can move by an hour depending on the date, so pick the offset that applies on your travel day. If your journey has connections, you can either calculate the whole trip end to end or break it into legs and add them up. For converting a single time between zones rather than measuring a duration, use the time zone converter. The layover time calculator checks whether a connection leaves enough time, and the unit converter handles distances and other measurements.

Privacy

This calculator runs entirely in your browser. The dates, times and time zones you enter are never uploaded, never stored and never logged — close the tab and nothing remains. No account, no tracking, just instant local maths.