Stop Guessing.Start Training.
Every runner wonders: "What pace should I run?" "What time can I finish?" We give you the exact, science-based answers — for free.
Free Athletics Calculators
Science-based tools to help you train smarter
Race Time Predictor
Predict equivalent race times across distances using the Riegel formula.
Pace Calculator
Find your pace, speed, and finish time from any distance and duration.
Training Zones
Get personalized heart rate and pace zones from a recent race result.
Calorie Burn
Estimate calories burned during running based on weight and effort.
Stop Guessing. Start Training.
Every runner has these questions. We give you the exact answers.
"I don't know what pace to run for my marathon"
Enter any race time → Get exact pace for every distance
"I have no idea what time I can realistically finish"
Input a recent race → Predict your exact finish time
"I'm training too hard or too easy"
Get personalized zones → Know exactly where to train
"I don't know how many calories I burn running"
Enter weight + distance → Get exact calorie burn
How It Works
Get science-based training data in 3 simple steps
Enter Your Data
Input your recent race time, distance, or current fitness level. Takes less than 30 seconds.
Get Instant Results
Our science-based algorithms calculate your exact pace, zones, or predicted times immediately.
Train Smarter
Use your personalized data to structure every run — easy days easy, hard days hard.
Get Your Free Race Day Checklist
Join runners who use our science-based tools. Get a free race day checklist and training tips weekly.
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Built with Science-Based Formulas
Our calculators use the same formulas trusted by coaches and sports scientists
Riegel Formula
The race time predictor uses the Riegel model (1981), a scientifically validated formula for predicting equivalent race performances across distances.
MET Values
The calorie burn calculator uses MET values from the Compendium of Physical Activities, the standard reference for energy expenditure research.
Training Zones
Training zones are calculated using the 80/20 rule and lactate threshold principles, the same methodology used by elite coaches.
Ready to Train Smarter?
Start with our most popular calculator and see what your training data tells you.
Try Race Predictor Free