Time Duration Calculator
Calculate the duration between two times.
How long between two times
Working out how much time lies between two clock times — a start and an end — comes up constantly, and it is fiddlier than it looks once you cross noon, midnight, or hours in the sixties. This calculates the duration between two times cleanly.
Enter a start and end time to find the duration.
Why time arithmetic trips people up
Time is awkward to do arithmetic with because it is not decimal — there are sixty minutes in an hour, not a hundred, so you cannot just subtract the numbers. Crossing midnight adds another twist, where the end time is earlier on the clock than the start but later in reality. These are exactly the points where hand calculations go wrong, turning a simple question into an error-prone chore. The calculation handles the base-sixty arithmetic and the day boundary for you. Working out durations correctly matters for timesheets, billing, cooking, travel and countless everyday situations where you need to know not what time it is but how much time has passed, which the clock does not tell you directly.
Common questions
Why can't I just subtract the times?
Because time is not decimal — sixty minutes to an hour, not a hundred — and crossing midnight makes the end time earlier on the clock but later in reality.
What is duration calculation used for?
Timesheets, billing, cooking, travel and anywhere you need to know how much time has passed rather than what time it is.
Is anything uploaded?
No. The calculation happens in your browser.