Find your optimal training zones (Karvonen method)
Training in specific heart rate zones optimizes your workouts. This calculator uses the Karvonen method (factoring in resting heart rate) for more accurate zones. Zone 1 is recovery, Zone 5 is maximum effort. Max heart rate is estimated as 220 minus your age.
Heart rate zone training ensures you're exercising at the right intensity for your goal — whether that's fat burning, endurance, or peak performance. The five standard zones are calculated from your maximum heart rate (roughly 220 minus age): Zone 1 (50-60%) for recovery, Zone 2 (60-70%) for base endurance and fat burning, Zone 3 (70-80%) for aerobic fitness, Zone 4 (80-90%) for anaerobic threshold and speed, and Zone 5 (90-100%) for maximum effort. Most recreational exercisers should spend 80% of training time in Zones 1-2 and only 20% in Zones 3-5 (the 80/20 rule). This calculator uses either the age-based formula or your actual measured heart rate data for more accurate zones.
It's an estimate with ~10-12 BPM standard deviation. Some people have naturally higher or lower max HR regardless of fitness. For accuracy, get a lab VO2max test or use the Karvonen formula with your resting heart rate.
Zone 2 (60-70%) burns the highest percentage of fat as fuel. However, higher zones burn more total calories per minute. For weight loss, total calorie burn matters more than fat percentage — but Zone 2 allows longer workouts.
Target HR = ((Max HR - Resting HR) × Intensity%) + Resting HR. It's more accurate than simple percentage because it accounts for your fitness level via resting heart rate. A fit person with low resting HR gets different zones.
Beginners: mostly Zone 2 with some Zone 3. Experienced: 80% Zone 1-2, 20% Zone 4-5 (polarized training). Avoid spending too much time in Zone 3 ('grey zone') — it's too hard for recovery but not hard enough for peak adaptation.
For zone training, yes — perceived effort is unreliable, especially for beginners. Chest straps are most accurate (~99%). Wrist-based (optical) monitors are 92-97% accurate and more convenient. Either works for zone training.