Karvonen Target Heart Rate
Calculator

Karvonen incorporates your resting heart rate by calculating heart rate reserve (max minus resting) and applying the target percentage to that reserve before adding resting heart rate back. This produces zones tailored to your individual cardiovascular fitness rather than a generic percentage of max alone.

A fitter person with a low resting heart rate has a larger heart rate reserve, so the same target percentage translates to a higher absolute target heart rate than for someone with a higher resting rate. This makes Karvonen zones more individualized than max-HR-only calculations.

Target HR = ((max HR − resting HR) × intensity%) + resting HR. You need three inputs: estimated or tested max heart rate, resting heart rate, and your desired intensity percentage for the zone.

Take it first thing in the morning before getting out of bed, ideally averaged over several days for stability, since a single noisy reading can skew your target zones. A wearable device's overnight resting heart rate average is also a reliable source.

It's generally considered a better approximation of true training intensity because it accounts for individual cardiovascular fitness through resting heart rate, but it still relies on an estimated or tested max heart rate, which carries its own uncertainty. Neither method eliminates the need for perceived-effort checks alongside heart rate data.