Put in a recent race and it predicts the rest with Riegel's formula: T2 = T1 × (D2 / D1)^1.06.

Tool
Recent race
mm:ss or h:mm:ss
– 5K pace
– marathon pace
Riegel's formula, so it assumes you've trained for the longer distance.

Notes

  • The further the prediction is from the race you put in, the less you should trust it.
  • Nothing is sent anywhere, it's all worked out in the page.