Zone 2 Heart Rate Calculator

About this calculator

Zone 2 is the second of five heart-rate training zones used in endurance sports, sitting at roughly 60-70% of maximum heart rate. It corresponds to an easy, conversational effort where the body relies predominantly on fat oxidation and aerobic metabolism rather than glycolysis, and it is the pace most elite endurance athletes spend the bulk of their weekly training volume in, following the widely cited '80/20' polarized training model.

Training in Zone 2 is believed to build mitochondrial density, capillary networks and the aerobic base that higher-intensity work is later layered on top of, without accumulating the fatigue and injury risk that comes with frequent hard sessions. It has been popularized in endurance coaching circles by figures like exercise physiologist Iñigo San Millán and longevity physician Peter Attia, and it overlaps closely with Phil Maffetone's older MAF (Maximum Aerobic Function) method.

This calculator estimates your max heart rate using the standard 220 minus age formula and returns the 60-70% range in beats per minute, giving you the target zone to hold during easy runs, rides or other aerobic base-building sessions.