Pace

a running calculator

Plug in a distance and a time. See your pace per kilometer, and what a marathon would cost you holding it.

5:00/ km
8:03 / mi
12.00 km/h
5K25:00
10K52:07
Half1:55:00
Marathon3:59:47

Predictions use the Riegel formula: t₂ = t₁ · (d₂ / d₁)^1.06. Reasonable for distances within ~3× of your input, less so at the extremes (a 5K time over-predicts a marathon for most runners).