Running Calculators
Pace calculator, training pace estimator, and race time predictor.
Edit any field and the rest fill in automatically.
Format: MM:SS or H:MM:SS
Format: MM:SS or H:MM:SS
Methodology
Pace Calculator
Edit any field and the others fill in around it. Covers min/mile, min/km, mph, kph, distance, and time. Race estimates appear once you have a pace.
Pace Estimator
Enter a race result and get your Aerobic Index, an effective aerobic capacity derived from your performance, plus training paces across five intensity zones.
The oxygen cost of running at velocity v (m/min):
VO₂ = -4.60 + 0.182258v + 0.000104v²
Sustainable fraction of VO₂max for duration t (minutes):
%VO₂max = 0.8 + 0.1894393·e^(-0.012778t) + 0.2989558·e^(-0.1932605t)
Aerobic Index = VO₂ / %VO₂max. Zone percentages (59–110%) come from established exercise physiology research.
Race Predictor
T₂ = T₁ × (D₂/D₁)^1.06
The exponent 1.06 captures the fact that longer races are harder than a straight pace scale suggests. Most accurate when predicting distances within two or three times the input distance.
Source: Riegel, P.S. (1981). Athletic Records and Human Endurance. American Scientist 69(3), 285–290.
Note: Results are estimates based on population averages. Individual responses vary. Nothing here is medical advice. Talk to a doctor or coach before changing your training or nutrition.