Karvonen Target Heart Rate Calculator

About this calculator

The Karvonen method sets a training heart rate around your heart rate reserve (HRR) rather than a flat percentage of maximum heart rate, which makes it more personal because it accounts for your actual resting heart rate. HRR is simply HRmax − HRrest, and the target heart rate is THR = (HRR × %intensity) + HRrest, where HRmax is commonly estimated as 220 minus age.

Because two people with the same maximum heart rate can have very different resting rates depending on fitness level, the Karvonen formula gives fitter individuals a higher, more accurate target than percent-of-max alone. Exercise physiologists, personal trainers and coaches use it to set cardio and interval zones — for example, 60–80% intensity for a moderate aerobic zone — and this calculator applies the formula from your age, resting heart rate and chosen intensity.