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Speed Calculator
How fast was that, on average? Enter distance and time and see the speed in three units.
Average speed
How it works
Speed = distance ÷ time km/h ÷ 3.6 = m/s km/h × 0.621371 = mph
Worked example: 120 km in 2 hours is 120 ÷ 2 = 60 km/h, which is 60 ÷ 3.6 = 16.67 m/s and 60 × 0.621371 = 37.28 mph. For 100 km in 2 hours the speed is 50 km/h.
Frequently asked questions
Is this average speed or top speed?
Average speed over the whole trip: total distance divided by total time, including any stops. A speedometer reading at one moment can be higher or lower.
What if the time is zero?
The speed is shown as 0, not an error. Dividing by zero has no meaningful speed, so the calculator quietly treats it as no trip.
Can I use miles instead of kilometres?
Convert first: miles × 1.60934 = kilometres. A 60-mile trip is about 96.56 km, so enter 96.56 as the distance.
Why three units?
Road signs use km/h or mph depending on the country, and physics problems usually want m/s. One input gives all three, so no second conversion is needed.
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