Running Pace & Race Predictor

Calculate your running pace or predict your finish times for upcoming races based on your current fitness.

Distance

Unit

Total Time

Hrs

Min

Sec

Average Pace

08:02

min / mi

05:00 Pace (min/km)

7.46 Speed (mph)

12.00 Speed (km/h)

Recent Race Distance

Finish Time

Hrs

Min

Sec

Predicted Race Times

00:25:00 5K

00:52:05 10K

01:55:18 Half Marathon

03:59:52 Full Marathon

The Runner's Math

Whether you're aiming for a personal best or just tracking a training run, understanding the math behind running is key to hitting your goals.

Pace vs. Speed: Speed is how far you travel in an hour (mph or km/h). Pace is the metric runners prefer: how many minutes it takes to complete exactly one mile or one kilometer.
The Riegel Formula: The Race Predictor uses a formula created by research engineer Peter Riegel in 1977. It states that a runner's time ($T$) for a new distance ($D$) relates to a recent performance via the equation: $T_2 = T_1 \times (D_2 / D_1)^{1.06}$.
Predictor Limits: Riegel's formula assumes you have trained adequately for the target distance. A great 5K time will only predict a great marathon time if you have actually done the long runs required to survive 26.2 miles!