Heart Rate Zone Calculator
Estimate max heart rate and five training zones from age — in your browser.
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Tool workspace
Required for Karvonen. Measure at rest (e.g. morning before rising).
Educational training-zone estimates only — not medical advice. Max HR uses 220 − age (Fox). Runs locally in your browser; measurements are not uploaded.
How it works
Estimated max HR uses the Fox formula: 220 − age.
Default method (% of max HR): Zone 1 very light 50–60%, Zone 2 light 60–70%, Zone 3 moderate 70–80%, Zone 4 hard 80–90%, Zone 5 maximum 90–100% of HRmax.
Karvonen (heart-rate reserve): target = ((HRmax − HRrest) × intensity%) + HRrest for the same zone percentages. Resting HR is required for Karvonen.
Results update as you type. Empty incomplete inputs clear the result—no error. Out-of-range values show a validation message.
Disclaimer: educational estimates only — not medical, clinical, or training advice. Age-based max HR is an approximation.
Examples
- Age 30, % of max → Max HR 190; Zone 3 about 133–152 bpm
- Age 30, resting 60, Karvonen → Max HR 190; Zone 3 about 151–164 bpm
Privacy
FAQ
Is this medical advice?
No. Results are educational training-zone estimates only and are not medical or clinical advice.
Are my measurements uploaded?
No. Calculation runs entirely in your browser. We do not log what you enter.
What is the difference between % of max and Karvonen?
% of max scales zones from estimated max HR alone. Karvonen also uses resting heart rate (heart-rate reserve), which often better reflects individual fitness.
Do I need an account?
No. All published tools work for guests without login.