Free tools
Calculators for the numbers athletes look up most: heart-rate zones and Zone 2, pace, race predictions, VO2max and sleep debt. Everything runs in your browser; nothing you type leaves it.
Free tools
- Heart rate zone calculator: your five zones and Zone 2 Your five zones and Zone 2 from max heart rate, heart rate reserve or threshold.
- Running pace calculator: pace, time and distance Any two of distance, time and pace give you the third, with race splits.
- Race time predictor: 5K, 10K, half marathon and marathon One recent race predicts your 5K, 10K, half marathon and marathon times.
- VO2max calculator from a race time or resting heart rate Estimate VO2max from a race or your heart rates, and compare it with your watch.
- Sleep debt calculator: how much sleep you owe Your last 14 nights against your sleep need: the debt, and how long to pay it back.