Heart Rate Zone Calculator
How it works
Maximum heart rate is estimated as 220 − age. Each of the five zones is a percentage band of that maximum: Very light 50–60%, Light 60–70%, Moderate 70–80%, Hard 80–90%, Maximum 90–100%.
Add a resting heart rate and the calculator switches to the Karvonen method. Instead of taking each percentage of max heart rate directly, it takes it of heart rate reserve — max minus resting — and adds resting back on: target = (max − resting) × percentage + resting. That ties the zones to your own resting baseline rather than age alone, which is why two people of the same age with different resting heart rates get different Karvonen zones from the same age-based max.
Frequently asked questions
How accurate is 220 minus age?
It is a population-average formula, not a measurement of you specifically — actual maximum heart rate at a given age varies by several beats either way between individuals. Treat the zones below as training guidance rather than a number to hit exactly.
What does adding a resting heart rate change?
Without it, each zone is a flat percentage of your estimated max. With it, the calculator switches to the Karvonen method, which works from heart rate reserve — max minus resting — rather than max alone, so the zones reflect your own resting baseline instead of age alone.
Are these medical thresholds?
No. They are training zones used to gauge effort during exercise, not diagnostic limits. If you have a heart condition or are new to structured exercise, check with a clinician before training to a target zone.