Heart Rate Zones Calculator (Karvonen Method)
Training in the right heart rate zone is key to achieving specific fitness goals, whether you want to burn fat, build endurance, or improve speed. This calculator uses the Karvonen method, which factors in your resting heart rate for more personalized zones than simple percentage-of-max methods.
The Karvonen method calculates Target Heart Rate (THR) using the formula: THR = ((Max HR – Resting HR) × % Intensity) + Resting HR. Maximum heart rate is estimated as 220 minus your age (Fox formula). The five training zones are: Zone 1 (50–60%) for warm-up and recovery; Zone 2 (60–70%) for fat burning and endurance base building; Zone 3 (70–80%) for aerobic fitness and cardiovascular improvement; Zone 4 (80–90%) for anaerobic threshold and speed work; Zone 5 (90–100%) for maximum effort sprints. Most people benefit most from spending the majority of training time in Zones 2–3.