Race Predictor
Predict your race times using the scientifically-proven Riegel formula
Known Race Distance
Known Race Time
Your Pace
5:00min/km
8:03min/mile
About the Riegel Formula
The Riegel formula, developed by Peter Riegel in 1977, is a widely-used method for predicting race times. It accounts for the natural slowdown that occurs as race distance increases, using the formula:
T2 = T1 x (D2 / D1)^1.06
Note: Predictions assume similar training and conditions. Actual times may vary based on fitness, terrain, weather, and race strategy.
Predicted Race Times
1 Mile
1mi7:31
Pace:4:40 /km
7:31 /mi
5K
5K25:00
Pace:5:00 /km
8:03 /mi
Input Distance
10K
10K52:07
Pace:5:13 /km
8:23 /mi
15K
15K1:20:07
Pace:5:20 /km
8:36 /mi
Half Marathon
HM1:55:00
Pace:5:27 /km
8:46 /mi
Marathon
M3:59:47
Pace:5:41 /km
9:09 /mi
Detailed Breakdown
| Distance | Time | Pace (min/km) | Pace (min/mi) |
|---|---|---|---|
1 Mile 1.61 km / 1.00 mi | 7:31 | 4:40 | 7:31 |
5KInput 5.00 km / 3.11 mi | 25:00 | 5:00 | 8:03 |
10K 10.00 km / 6.21 mi | 52:07 | 5:13 | 8:23 |
15K 15.00 km / 9.32 mi | 1:20:07 | 5:20 | 8:36 |
Half Marathon 21.10 km / 13.11 mi | 1:55:00 | 5:27 | 8:46 |
Marathon 42.20 km / 26.22 mi | 3:59:47 | 5:41 | 9:09 |
Tips for Accurate Predictions
- 1.Use a recent race time (within the last 2-3 months) for the most accurate predictions.
- 2.The formula works best when comparing similar race distances (e.g., 5K to 10K rather than 1 mile to marathon).
- 3.For longer distances, adequate training volume is essential to achieve predicted times.
- 4.Consider course difficulty, weather conditions, and elevation when setting race goals.