Heart Rate Zone Calculator

See your heart rate zones calculated two ways: Karvonen and percentage of max HR.

Resting HR: measure first thing in the morning before getting up.
Max HR: use a value from an all-out effort. Don't know it? Start with 220 minus your age. That's the default your watch already uses, and it can miss by 10–12 BPM in either direction, so replace it with a real reading when you have one.

Last updated 6 August 2026

Karvonen / HRR Recommended

Target HR = RHR + % Intensity × (Max HR − RHR)

Zone % Intensity BPM
% of Max HR

Target HR = % Intensity × Max HR

Zone % Intensity BPM

The two methods use the same percentages and land about 20 BPM apart, so which one your watch uses decides which range you get.

Put these numbers to work with our guides to Zone 2 training and VO₂ max intervals.

Or skip the mental math on the run: RunBeat coaches your zones through your headphones in real time.