Speed, distance and time calculator

Know two of speed, distance and time? Get the third.

Formula Science & engineering

Average speed

Rounded for display

In km/h: ≈ 12.0557 km/h
In mph: ≈ 7.4911 mph
In m/s: ≈ 3.3488 m/s
Pace per distance unit: 4:59

How it works

Speed is distance divided by time. Rearranged, distance is speed times time, and time is distance divided by speed.

The calculator converts everything to metres and seconds first, using exact factors (1 mile = 1609.344 m, 1 nautical mile = 1852 m), then converts the answer to the units you chose. The result is an average: it assumes a steady speed for the whole trip.

Formula

speed = distance ÷ time
distance = speed × time
time = distance ÷ speed
1 m/s = 3.6 km/h

Worked example

A marathon of 42.195 km run in 3 h 30 min is an average of 42.195 ÷ 3.5 ≈ 12.06 km/h, a pace of 4:59 per km. At 12 km/h the same distance takes 3:30:59.

Questions people ask

How do I convert km/h to m/s?

Divide by 3.6: 90 km/h = 25 m/s. To go back, multiply by 3.6.

What is pace?

The time taken per unit of distance, such as minutes per kilometre. It is the reciprocal of speed and is common in running.

Is average speed the mean of my speeds?

Not in general. Driving 60 km at 60 km/h and 60 km at 30 km/h takes 3 hours for 120 km, an average of 40 km/h, not 45.