Heart Rate Zone Calculator
Training zones estimated from age and resting heart rate using the Karvonen method.
Estimated maximum heart rate: 185 bpm (220 − age, a common estimate).
Zone 1 · Recovery
Easy effort — supports active recovery and base aerobic health.
124–136
Zone 2 · Aerobic base
Conversational pace — the workhorse zone for building aerobic efficiency.
136–148
Zone 3 · Tempo
Comfortably hard — improves aerobic capacity and lactate clearance.
148–160
Zone 4 · Threshold
Hard, sustainable for shorter periods — raises your lactate threshold.
160–173
Zone 5 · Peak
Maximal effort — short intervals only, builds top-end capacity.
173–185
Zones are estimated using the Karvonen (heart rate reserve) method. Individual max heart rate varies — a supervised fitness test gives a more precise figure than the age-based formula.