Free running calculators for pace & race times
Running Calcs is a hub of focused tools for runners. Use the running pace calculator, marathon pace calculator, or marathon time calculator to plan training and race-day pacing.
Popular calculators
The tools runners reach for most often.
Free pace converter for runners. Convert min/km to min/mile, mile pace to km pace, and running speed in km/h or mph for treadmill and track workouts.
Open calculatorFree running pace calculator for km and miles. Enter distance, finish time, or target pace to work out the missing value, with kilometre splits.
Open calculatorFree marathon time calculator and race predictor. Estimate 5K, 10K, half marathon, and marathon finish times from a recent race using Riegel's formula.
Open calculatorPopular goal-time calculators
Pre-filled pace calculators for common race targets — the fastest way to see required min/km and splits.
Running calculators by goal
Jump straight to the calculator that matches your search.
- Running pace calculator
Work out pace, finish time, or distance with km splits.
- Marathon pace calculator
Plan even 42.2 km pacing from your goal time.
- 5K pace calculator
Target finish time and per-km splits for 5 km.
- Half marathon pace calculator
Pacing and splits for a 21.1 km half marathon.
- Pace converter (mile to km)
Convert min/mile to min/km, km/h, and mph.
- Marathon time calculator
Predict marathon finish time from a recent race.
All calculators
Conversions, pacing, race prediction, and training tools.
Convert running distances between kilometres and miles. Quickly switch 5K, 10K, half marathon, and marathon distances between metric and imperial.
Free pace converter for runners. Convert min/km to min/mile, mile pace to km pace, and running speed in km/h or mph for treadmill and track workouts.
Free running pace calculator for km and miles. Enter distance, finish time, or target pace to work out the missing value, with kilometre splits.
Free marathon time calculator and race predictor. Estimate 5K, 10K, half marathon, and marathon finish times from a recent race using Riegel's formula.
Calculate Daniels training paces from a recent race. Get easy, marathon, threshold, interval, and repetition pace targets in min/km and min/mile.
Convert treadmill speed and incline to equivalent outdoor running pace. Account for grade using the ACSM metabolic cost formula.
Estimate calories burned running from body weight, distance, and pace. Uses Compendium of Physical Activities MET values for running speed.
Calculate age-graded performance from race time, age, and sex. Compare results across ages using WMA-style age-grading factors.
Adjust target running pace for elevation gain using the Minetti energy cost model. Plan effort-based pacing on hilly courses.
Estimate maximum heart rate from age using common running formulas. A starting point for heart rate zone training and effort guidance.
Calculate heart rate reserve and training zones from resting and max heart rate. Plan easy, tempo, and threshold efforts with zone targets.
Estimate VO2 max from a recent race distance and finish time. A practical fitness benchmark for runners tracking aerobic progress.
Built for runners, by a runner
Running Calcs is a growing collection of simple, focused calculators built to help runners train smarter. Fast, accurate, and designed specifically for the questions you face in training and on race day.
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