🏃 Health & Fitness
Heart Rate Zone Calculator
The Karvonen method builds zones from your heart rate reserve — the gap between resting and maximum heart rate — which makes the zones personal rather than generic. Zone 2 builds aerobic base; zone 4 and above develops threshold and speed.
How it works
Age
Resting heart rate
Maximum heart rate
Zone 2 (aerobic base) from
Zone 2 to
Zone 3 (tempo) from
Zone 4 (threshold) from
Zone 5 (max) from
Frequently asked questions
How do I use the Heart Rate Zone Calculator?
Fill in the fields above — the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.