Heart rate zones calculator
Training heart-rate zones tell you how hard to work for a given goal, from easy recovery to maximal effort. FitCalcs uses the Karvonen method, which is more personal than a flat percentage of your max heart rate because it factors in your resting pulse. Enter your age and resting heart rate, or your measured max, and you get five zones in beats per minute. Most endurance gains come from zone 2, an easy conversational pace. Check with a GP before hard training if you have a heart condition. This is general information.
How this is worked out
FitCalcs uses the Karvonen method, which is more personal than a flat percentage of max heart rate because it accounts for your resting pulse (your heart-rate reserve):
max HR = 220 − age (unless you enter your own)
reserve = max HR − resting HR
zone HR = (reserve x intensity %) + resting HR
The five zones run from easy recovery (50 to 60% of reserve) to maximal effort (90 to 100%). Most endurance gains come from zone 2, an easy conversational pace. The 220 minus age estimate can be 10 to 12 bpm out, so a measured max is better if you have one.
Informational only. Check with a GP before hard training if you have a heart condition. Editorially reviewed by FitCalcs, with each figure citing its source.
Calculators and Data Desk, FitCalcs
FitCalcs' editorial desk builds and documents the calculators, citing the underlying equation and the UK dataset behind every number. Health-related tools are editorially reviewed, with figures cited to named UK sources.
Last reviewed: 12 June 2026