Running Calories
Estimate running calories with the ACSM equation.
Running Calculators
Calculate running pace and aerobic fitness or predict finish times for common race distances.
Pace & Fitness
Pace
Convert between distance, time, pace, and speed.
Running Splits
Build even cumulative splits for a target time.
Training Paces
Estimate training ranges from a recent race.
Threshold Pace
Estimate threshold pace from race VDOT.
VDOT Calculator
Calculate VDOT and equivalent performances.
Weight vs Pace
Model race pace at a modest range of bodyweights.
Track Splits
Calculate laps and track checkpoint times.
Running Pace Converter
Convert pace and speed units with same-pace times.
Maximum Aerobic Speed Calculator
Estimate field-test MAS and percentage training speeds.
Heart Rate & Aerobic Fitness
VO₂ Max
Estimate aerobic fitness from a Cooper test.
Max Heart Rate
Compare age-based maximum heart-rate estimates.
Heart Rate Zones
Estimate five training heart-rate zones.
Race Predictors
5K
Predict a 5K time from a recent performance.
10K
Predict a 10K time from a recent performance.
Half Marathon
Predict a half marathon finish time.
Marathon
Predict a marathon finish time.
Using these tools
Race predictions work best when the reference effort is recent and conditions are similar. Terrain, weather, pacing, endurance, and preparation can all shift the result, so use predictions to guide targets rather than guarantee an exact finish time.