Speed Calculator
Calculate speed instantly with our free speed calculator. Enter distance and time in any units to get your speed in km/h, mph and meters per second.
About this tool
How fast was that run, drive, or flight, really? Our free speed calculator turns any distance and time into speed, shown in km/h, mph, and meters per second side by side.
Mix units freely - miles with minutes, meters with hours - the tool converts everything behind the scenes.
How to use
Enter the distance and pick its unit (kilometers, miles, or meters). Then enter the time it took and pick hours or minutes.
Press Calculate Speed to see your speed in all three common units. Great for runners checking pace, drivers estimating trips, and students verifying physics homework.
The math behind it
Speed equals distance divided by time. The calculator first converts your inputs to kilometers and hours, computes km/h, then converts: mph = km/h / 1.60934 and m/s = km/h / 3.6.
For example, 100 km in 2 hours is 50 km/h, which equals about 31.07 mph and 13.89 m/s. All three describe the exact same speed.
Frequently asked questions
What is the difference between speed and velocity?
Speed is how fast you are moving (a single number, like 50 km/h). Velocity is speed plus direction (50 km/h north). This calculator computes average speed - total distance divided by total time - which is what most everyday questions mean by how fast. Physicists use velocity when direction matters, such as round trips where average velocity can be zero.
How do I convert pace (min/km) to speed?
They are inverses. If your pace is 6 minutes per kilometer, that is 6/60 = 0.1 hours per km, so your speed is 1 / 0.1 = 10 km/h. In this calculator, just enter distance 1 km and time 6 minutes to get the same answer. Runners often think in pace, but speed makes comparisons across distances easier.
Why do cars use km/h or mph but science uses m/s?
Convention and convenience. Road speeds in km/h or mph give friendly numbers (50-120) for everyday driving. Scientists prefer meters per second because it fits the metric system cleanly in physics equations - no conversion factors cluttering the math. This calculator shows all three so you never have to convert by hand.
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