Speed, distance and time calculator
Enter two of the three values (speed, distance, time) to instantly calculate the third, with automatic conversion between km/h, m/s, mph, kilometers, meters and miles. 100% local calculation, with no server connection.
How it works
The relationship between speed, distance and time rests on a single physics formula: speed = distance / time. This tool rearranges the formula depending on the value you want to find, after converting each quantity to a common unit (meters and seconds) to guarantee a correct result whichever combination of units you choose.
Why convert to "common" units before calculating?
Mixing kilometers with meters per second without converting would produce a result that is off by a factor of 1,000 or more. This tool always converts speed and distance to meters and seconds internally, calculates the result, then converts back to the output unit you chose — so you never have to do the conversion yourself.
Can I calculate a travel time in hours and minutes?
Yes. When you calculate speed or distance, time is entered as separate hours and minutes; when you calculate time, the result is displayed directly in that readable form (hours, minutes, seconds) rather than as decimal hours.
The calculation runs entirely in your browser — no data is sent to a server.