Karvonen Target Heart Rate Calculator

About this calculator

The Karvonen method sets a training heart rate using heart rate reserve (HRR) rather than a flat percentage of max heart rate: Target HR = ((HRmax - HRrest) x %Intensity) + HRrest. Because it factors in your resting heart rate, it accounts for individual fitness level — two people with the same max heart rate but different resting rates get different, more personalized target zones.

Coaches and exercise physiologists favor Karvonen over the simple ’% of max HR’ method because it’s more accurate at low-to-moderate intensities, which is where most base and recovery training happens. A 65-75% HRR zone is typical for endurance-building runs and rides, while 80-90% HRR marks threshold and interval work; the same percentage against a fitter (lower resting HR) or less-fit (higher resting HR) athlete yields a meaningfully different target when reserve is used instead of max alone.

This calculator takes your max and resting heart rate along with your target intensity percentage and returns the beats-per-minute you should aim for during that session.