Heart Rate Zone Calculator
Target heart rate zones (Karvonen) for training
Use this when you need a fast, accurate result — no sign-up, works entirely in your browser.
Estimated max HR—
Zone 1: 50-60% (warm-up)—
Zone 2: 60-70% (fat burn)—
Zone 3: 70-80% (aerobic)—
Zone 4: 80-90% (anaerobic)—
How to Use
- Enter your details into the fields above.
- Click the calculate button to get your result instantly.
- Use the clear button to start a new calculation.
Example
- Age 30, resting 65 bpm → Estimated max 190 bpm; Zone 2 (fat burn) ≈ 140-152 bpm
- Age 40, resting HR 60 → Max HR 180 bpm; zones: Z1 120–132, Z2 132–144, Z3 144–156, Z4 156–168
Formula
Karvonen: HR reserve = max HR − resting HR. Zone target = resting + reserve × intensity. Max HR is estimated as 220 − age.
About Heart Rate Zone Calculator
Target heart rate zones (Karvonen) for training. This free online tool gives you fast, accurate results without registration or downloads.
Everything runs locally in your browser, so your data is never uploaded or stored — privacy first.
Frequently Asked Questions
Is this tool free to use? +
Yes, it is completely free with no registration or download required.
Is my data private? +
Yes. Everything is processed locally in your browser. Nothing is uploaded or stored on our servers.
Does it work on mobile? +
Yes, it works on any device — phone, tablet, or desktop.