Race Prediction Calculators
Predict race times using proven formulas like Riegel, VDOT and age grading.
Marathon Time Predictor
Predict your marathon time from a shorter race result.
Half Marathon Predictor
Predict your half marathon time from 5K or 10K results.
10K Predictor
Predict your 10K time from a 5K or parkrun result.
5K Predictor
Predict your 5K time from shorter or longer race results.
Parkrun Predictor
Predict your parkrun time from other race distances.
Ultra Predictor
Predict ultra marathon times for 50K, 50mi, 100K and 100mi.
Riegel Formula Calculator
Use the Riegel formula to predict race times from any distance.
VDOT Calculator
Calculate your VDOT score and equivalent race performances.
Age Grade Calculator
Calculate your age-graded performance percentage.
Equivalent Performance Calculator
Find equivalent performances across different race distances.
10 free calculators in Race Prediction
Race Prediction Calculators
Predict your race times using proven formulas including the Riegel formula (T2 = T1 × (D2/D1)^1.06), VDOT calculations, and age grading. Enter a recent race result and get predicted times for any distance from parkrun to ultra marathon.
These calculators are based on established sports science research and are widely used by coaches and athletes worldwide.