Number One Running Pace Calculator
Turn a distance into a watch split.
Work out running pace, finish time, or how far you went. Kilometres or miles, 5K through marathon — all in your browser, nothing uploaded.
Your result
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per km
Even splitBackground
How this running pace calculator works
Pace is time divided by distance. A 5K in 25:00 is 5:00 per kilometre, or about 8:03 per mile. The same maths runs the other way: pick a pace and a race, and you get a finish time; pick a pace and a time, and you get how far you went.
Even splits and race predictions
The cards labelled even split assume you hold the same pace from start to finish. Real races rarely do — hills, crowds, and a fast last kilometre all move the watch. When you enter a distance and a time, we also sketch other race times with Riegel’s formula (time scales with distance to the power 1.06). It is a popular rule of thumb, not a promise: it tends to be optimistic if you have not trained for the longer distance.
Kilometres and miles
One mile is 1.609344 kilometres. We always show both paces so a kilometre session and a mile split can live on the same watch. Road 5K and 10K are 5.000 and 10.000 km; a half marathon is 21.0975 km; a marathon is 42.195 km.