Velocity from distance and time — with unit conversion and average velocity.
Displacement is the straight-line change of position, with a sign for direction. On a round trip it can be zero even though the distance travelled was large.
Velocity
VelocityHow to use this tool
Enter the distance travelled and the time taken, each in whatever unit you have — kilometres, metres, miles or feet, and hours, minutes or seconds.
Pick the unit for the headline result — km/h, m/s, mph or knots. All four are shown anyway, plus pace per kilometre and per mile for runners.
Speed is distance ÷ time. It updates live as you type, with the conversions already done.
Enter a signed displacement (straight-line change of position, negative for the opposite direction) to see average velocity — the quantity that can be smaller than speed, zero on a round trip, or negative.
Formula & worked example
Worked example: 100 km in 2 hours gives velocity 50 km/h, which is 13.8889 m/s and 31.0686 mph. Another: 100 metres in 10 seconds gives 10 m/s, which is 36 km/h and 22.3694 mph. Average-velocity example: a displacement of 60 km in the same 2 hours gives average velocity 30 km/h — less than the 50 km/h speed, because the straight-line displacement is shorter than the distance actually travelled.
Limitations — read this before you rely on it
This is average velocity over the whole journey, not instantaneous velocity at a moment — a car that speeds up and slows down can share the same average as one that cruises steadily. It also assumes a single straight-line distance or displacement; for a winding route, use the displacement (not the odometer distance) for average velocity. Time must be greater than zero, and results are rounded to 4 decimals for display.
Frequently asked questions
A velocity calculator finds velocity from distance and time: velocity = distance ÷ time. Enter the distance and the time in any units, and it returns the result in km/h, m/s, mph and knots, plus pace — and, in Advanced, the average velocity from a signed displacement.
Velocity formula: v = d ÷ t. For 100 km in 2 hours: v = 100 ÷ 2 = 50 km/h. To convert: 50 km/h × 1000 ÷ 3600 = 13.8889 m/s, and 50 km/h ÷ 1.609344 = 31.0686 mph.
Speed is a scalar — how fast, with no direction. Velocity is a vector — how fast and in which direction. Speed uses total distance travelled; average velocity uses displacement (straight-line change of position). On a round trip, average velocity is zero even though average speed is not.
Multiply m/s by 3.6 to get km/h, and divide km/h by 1.609344 to get mph. So 10 m/s = 36 km/h = 22.3694 mph. This calculator converts automatically, so you never need to do it by hand.
Yes — average velocity = displacement ÷ time, and displacement carries a sign for direction. A displacement of −20 km in 2 hours gives average velocity −10 km/h: the minus sign means the motion was in the opposite direction to the reference, not that something went wrong.