Use a recent race result to predict what you could run at other distances, from the mile to the marathon.
How this works
Predictions use Peter Riegel’s formula: T2 = T1 × (D2 ÷ D1)1.06, where T1 and D1 are your recent race time and distance.
It works best between about 3.5 minutes and 4 hours and assumes you have trained for the longer distance. Use a recent, all-out race for the most reliable result.
Stop exercising and rest if you feel pain, dizziness or unusual shortness of breath. Check with your doctor before starting a new exercise program.