Heart Rate Zone Calculator
Calculate your five heart rate training zones using the Karvonen method. Uses your age-predicted maximum heart rate and resting heart rate to determine personalized intensity zones.
Optional. Defaults to 72 bpm if left blank.
How This Calculator Works
Formula: Karvonen Method (Heart Rate Reserve)
The Karvonen method calculates training zones based on heart rate reserve (HRR): HRR = Max HR - Resting HR. Target HR = (HRR x intensity%) + Resting HR. Maximum heart rate is estimated as 220 - age. Five zones are defined: Zone 1 (50-60% HRR) for recovery, Zone 2 (60-70% HRR) for aerobic base, Zone 3 (70-80% HRR) for tempo/threshold, Zone 4 (80-90% HRR) for lactate threshold, and Zone 5 (90-100% HRR) for VO2 max intervals.
Limitations
- The 220-age formula for max heart rate has a standard deviation of 10-12 bpm and may not match your actual max HR.
- Resting heart rate should be measured under standardized conditions for accuracy.
- Heart rate response to exercise is affected by medication, caffeine, dehydration, temperature, and fatigue.
- Heart rate zones are approximations — perceived exertion and pace should also guide training intensity.
These calculations are estimates based on established formulas. Individual results vary. Consult a healthcare professional before making significant changes to your diet or exercise routine.
Heart rate zone training is a structured approach to cardiovascular exercise that uses heart rate as a guide for workout intensity. By training in specific zones, you can target different physiological adaptations and build a comprehensive fitness base.
The Karvonen method, also known as the heart rate reserve method, is considered more accurate than simple percentage-of-max calculations because it accounts for your individual resting heart rate. Two people of the same age can have very different resting heart rates, which significantly affects their training zone boundaries.
The five standard training zones each serve a distinct purpose. Zone 1 (50-60% heart rate reserve) is for warm-ups, cool-downs, and active recovery. Zone 2 (60-70%) builds aerobic endurance and is the foundation of most training programs. Zone 3 (70-80%) develops the aerobic-anaerobic threshold. Zone 4 (80-90%) increases lactate threshold and the ability to sustain high-intensity efforts. Zone 5 (90-100%) targets maximum aerobic capacity (VO2 max) through short, intense intervals.
Most endurance training should occur in Zones 1 and 2. A common recommendation is the 80/20 rule: approximately 80% of training time at low intensity (Zones 1-2) and 20% at higher intensity (Zones 3-5). This polarized approach has been shown to produce better long-term adaptations than spending most training time at moderate intensity.
For the most accurate zones, know your actual maximum heart rate from a supervised max test rather than relying on the 220-age estimate. Also measure your resting heart rate first thing in the morning before getting out of bed, averaged over several days.