Enter your age and resting heart rate to get Z1–Z5 zones. The default is Karvonen (heart-rate reserve), which is more accurate than a flat percentage of maximum heart rate.
Frequently Asked Questions
How much does Karvonen differ from %HRmax?
Using heart-rate reserve can shift zones by 10–15 bpm between individuals of the same age.
How do I measure resting heart rate?
Take your pulse for one minute while still lying down, right after waking, for three days and use the lowest value.
Do I still need a formula if I have a measured max HR?
No — a measured value (from a max test or a hard 5K) beats any age-based estimate.
Gear runners ask about
GPS running watch
Pace, laps and alerts on your wrist
Chest strap heart-rate monitor
More reliable than wrist-based HR
Race day running shoes
Lightweight shoes for tempo and race pace
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