Calculators and guides for runners
Eight calculators that show their formula. You can check where a number comes from, or just take the result and go run.
- Max heart rate calculator Four formulas side by side, from your age. 181 bpm Intensity: zone 5 age 38, Tanaka
- Heart rate zone calculator Your 5 zones from max heart rate, by % of max or Karvonen. 129–142 bpm Intensity: zone 2 zone 2, Karvonen, resting 52
- Pace calculator Pace, speed or finish time: enter two, get the third. 7:15 /mi Intensity: zone 4 10K in 45:00
- Pace converter Minutes per mile to minutes per km, and back. 4:58 /km Intensity: zone 4 from 8:00 /mi
- Race time predictor Your mile to marathon times from one recent race. 3:27:01 marathon Intensity: zone 3 Riegel, from a 45:00 10K
- Cooper test calculator Your 12-minute run distance turned into VO2max and speed. 51.3 ml/kg/min Intensity: zone 5 2,800 m in 12 minutes
- Training pace calculator Easy, threshold and interval paces from a race time. 7:25–7:47 /mi Intensity: zone 4 threshold, from a 45:00 10K
- VO2max calculator Estimated VO2max (Daniels-Gilbert) from a race result. 45.3 ml/kg/min Intensity: zone 5 45:00 10K, Daniels-Gilbert
- Cooper test: how to test your maximal aerobic speed Kenneth Cooper's 12-minute run, from warm-up to the last lap. What your distance in miles says about your VO2max, and the treadmill speeds it gives you.
- Max heart rate by age: formulas and a real test 220 minus age misses by more than 10 beats for one adult in three. Three hill reps and a chest strap find your real max; the formulas only check it.
- Predict your marathon time from a half marathon A 1:55 half says 3:59:46 with Riegel. Checked on 2,303 recreational runners, half of them finished at least 10 minutes slower than that.
- Training paces from a race time: easy to intervals A 25:00 5K puts your easy runs at 9:44 to 11:38 per mile. Five training paces from one race, and the days to ignore them.
- Heart rate zones for running: how to set yours Percentage of max heart rate, or Karvonen? Both give five zones for running, but a slow resting pulse moves the easy ones up 15 to 25 beats.
- Gear reviews Shoes, GPS watches and heart rate straps, reviewed after I’ve run in them.
I’m Nicolas, I make this site. Running since 2024: a 1:37:40 half marathon, and two finishes at L’Arvor, a 35-mile race in Brittany.