Heart Rate Zones Calculator

Calculate your personalized heart rate training zones using the Karvonen method. Optimize your cardio workouts for fat burn, endurance, or performance.

This calculator builds five training zones with the Karvonen method, which works off heart rate reserve rather than raw percentages of maximum. Max Heart Rate is the simple 220-minus-age estimate — it depends only on your age and drops exactly one beat per year. Heart Rate Reserve subtracts your resting pulse from that maximum, and each zone is then a fixed percentage of the reserve added back on top of resting: Zone 1 recovery spans 50-60 percent, Zone 2 aerobic base 60-70, tempo 70-80, threshold 80-90, and VO2 max 90-100. The practical consequence is that the two inputs pull the zone boundaries in opposite directions on different schedules — each year of age trims one beat from the ceiling of every zone, while each beat added to your resting heart rate raises the floor of every zone and compresses the whole reserve. Per beat and per year the two inputs are equally strong, but resting heart rate typically varies far more between people than a few years of age, so it is usually the field that personalizes the result. The 220-minus-age maximum is a population average with wide individual spread, and the fixed zone percentages are conventions rather than measured lactate thresholds — lab or field testing beats any formula.