Heart Rate Reserve (Karvonen) Zones
Calculate heart rate reserve and Karvonen training zones from age, resting heart rate and maximum heart rate, free online.
About this calculator
Heart rate reserve = max HR − resting HR. Target heart rate = resting HR + (intensity % × reserve). If you don't know your measured max HR, it is estimated as 208 − 0.7 × age (Tanaka formula).