How to Use This Calculator
Enter your age and resting heart rate. The calculator uses the Karvonen formula to generate 5 personalized training zones. Use the zone table to guide your next workout — each zone delivers distinct physiological benefits.
Formula & Background
Max HR (MHR) = 220 − age. Heart Rate Reserve (HRR) = MHR − resting HR. Target HR = (HRR × zone%) + resting HR (Karvonen formula). This accounts for individual fitness level and is more accurate than MHR alone.
Zone ranges: Zone 1 (50–60%), Zone 2 (60–70%), Zone 3 (70–80%), Zone 4 (80–90%), Zone 5 (90–100%) of HRR.
Calculation Example
Age 30, resting HR 65 bpm: MHR = 190, HRR = 125.
Zone 2: (125×0.60+65) to (125×0.70+65) = 140–152 bpm (aerobic base, primary fat-burning zone).
Zone 4: 165–177 bpm (lactate threshold, race-pace training).
Expert Tips
- Zone 2 should make up 80% of total training volume for endurance athletes — it builds aerobic base without accumulating fatigue.
- Zone 5 intervals are high-reward but require full recovery; limit to 1–2 sessions per week.
- The 220−age formula has a ±10 bpm standard deviation — a lab VO2max test gives your actual MHR.
- If resting HR trends up by 5+ bpm over several mornings, it often signals under-recovery or early illness.