Heart Rate Zone Calculator
Calculate your heart rate training zones.
📐 Karvonen Method: Target HR = (Max HR − Resting HR) × Intensity% + Resting HR · Max HR = 220 − Age
Training in the correct heart rate zone is the foundation of effective cardiovascular conditioning. Each zone from 1 to 5 targets a different physiological adaptation — fat burning, aerobic base building, lactate threshold improvement, or VO2 max development. Training exclusively at moderate intensity (zone 3) — the "grey zone" — is the most common mistake in recreational exercise, producing mediocre results. This calculator gives you your personal heart rate zones based on your age and resting heart rate using the Karvonen formula.
📋 How to Use This Calculator
Enter your age and your resting heart rate (measure first thing in the morning before getting out of bed, averaged over 3 days). The calculator uses the Karvonen Heart Rate Reserve method — more accurate than age-only formulas — to give you 5 training zones. Zone 1 (50–60% HRR): active recovery. Zone 2 (60–70%): aerobic base, fat burning. Zone 3 (70–80%): aerobic fitness. Zone 4 (80–90%): lactate threshold. Zone 5 (90–100%): VO2 max, anaerobic.
💡 Key Facts & Information
Maximum heart rate estimation: most calculators use 220 − age. More accurate is 211 − (0.64 × age) (Tanaka formula). The Karvonen formula: Target HR = ((HRmax − HRrest) × %intensity) + HRrest. A 35-year-old with a resting HR of 65: HRmax = 185, HRR = 120. Zone 2 (60–70% HRR): 137–149 bpm. The 80/20 rule of training: elite endurance athletes do approximately 80% of training in Zone 1–2 and 20% in Zone 4–5. Most recreational athletes invert this, doing most work in Zone 3 — which is hard enough to be fatiguing but not intense enough to drive significant adaptation. Heart rate monitors (chest strap or optical wristband) are recommended for accurate zone training.