Calculate your 5 training zones using the Karvonen formula
Measure resting HR first thing in the morning before getting up.
Heart Rate Zones Calculator is a free health and wellness calculator that helps you calculate your 5 training zones using the karvonen formula. Understanding your body's metrics is the first step toward making informed health decisions. This tool uses clinically recognized formulas to provide instant, accurate estimates — though always consult a healthcare professional for medical advice.
Heart rate zones divide exercise intensity into 5 levels based on a percentage of your heart rate reserve (HRR). Each zone produces different physiological adaptations: Zone 1–2 builds aerobic base and burns fat efficiently; Zone 3 improves aerobic capacity; Zone 4–5 develops speed, power, and lactate threshold. Balancing time across zones optimizes fitness gains.
Zone 2 (60–70% of HRR) is often called the "fat burning zone" because a higher proportion of energy comes from fat at this intensity. However, higher intensity zones burn more total calories overall. For optimal fat loss, combine Zone 2 aerobic work with higher intensity sessions for maximum calorie expenditure and metabolic adaptation.
Measure your resting heart rate first thing in the morning before getting out of bed. Place two fingers on your wrist (radial pulse) or neck (carotid pulse) and count beats for 60 seconds (or 30 seconds × 2). For best accuracy, measure over 3 consecutive days and take the average. A normal resting HR is 60–100 bpm; athletes often measure 40–60 bpm.