Heart Rate Zone Calculator

Calculate personalized heart rate training zones with the Karvonen method.

Karvonen Zones

Max HR: 190 bpm · HRR: 130 bpm

Zone 1 (Recovery)

125 - 138 bpm

Zone 2 (Endurance)

138 - 151 bpm

Zone 3 (Tempo)

151 - 164 bpm

Zone 4 (Threshold)

164 - 177 bpm

Zone 5 (VO2 Max)

177 - 190 bpm

Formula: Karvonen method (target HR = resting HR + intensity × HRR).

Uses max heart rate and resting heart rate reserve (Karvonen) to build five intensity zones.

Set your inputs with real body or training data.
Confirm metric or imperial units, then run the calculation.
Review the output ranges and method assumptions before deciding.
Re-run with conservative and aggressive assumptions to compare outcomes.
Save your assumptions with a shareable URL, then compare one conservative and one aggressive scenario before acting.

Which formula is used here?

Uses max heart rate and resting heart rate reserve (Karvonen) to build five intensity zones.

Can I use metric or imperial units?

Yes. This tool supports both metric and imperial units and remembers your preference.

Is this medical advice?

No. This tool provides general fitness estimates and should not replace medical guidance.

Is this tool free and private to use?

Yes. AI Fit Hub tools are free, no-signup browser tools. Inputs stay in your browser unless you choose to share a URL.

Do these tools replace medical guidance?

No. These outputs are general fitness estimates — not medical advice.

Can I switch between metric and imperial units?

Yes. Every tool supports both systems and remembers your preference in localStorage.