Target Heart Rate Zones Calculator

Calculate cardiovascular training zones (Zone 1 to Zone 5) using the Karvonen Heart Rate Reserve formula for aerobic efficiency and endurance.

Estimated Max HR
187 BPM
Heart Rate Reserve (HRR)
122 BPM
Z1
Zone 1: Active Recovery
Warm-up, recovery, gentle blood flow
126 - 138 BPM
50% - 60%
Z2
Zone 2: Aerobic Base (Endurance)
Optimal mitochondrial & fat oxidation engine
138 - 150 BPM
60% - 70%
Z3
Zone 3: Tempo / Aerobic
Cardio fitness and breathing capacity
150 - 163 BPM
70% - 80%
Z4
Zone 4: Lactate Threshold
High intensity, stamina against fatigue
163 - 175 BPM
80% - 90%
Z5
Zone 5: VO2 Max & Anaerobic Peak
All-out power and sprint bursts
175 - 187 BPM
90% - 100%