Heart Rate Zone Calculator
Enter your max heart rate (or age to estimate it) to find your five training zones.
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Understanding Heart Rate Training Zones
Heart rate training zones divide your effort into five ranges, each targeting different physiological adaptations. Zone 2 (aerobic) builds endurance. Zone 4 (threshold) improves lactate clearance.
The simplest estimate of max heart rate is 220 minus your age, though individual variation is significant. If you know your true max HR from a test, enter it directly for more accurate zones.
Heart rate zones are calculated as percentages of maximum heart rate (HRmax). The commonly used formula HRmax = 220 − age gives a population average but has high individual variability (standard deviation ≈ ±10–12 bpm). A 40-year-old might have HRmax anywhere from 158 to 202 bpm and still be normal.
For more accurate HRmax, perform a field test: after thorough warm-up, run a hard 800m or mile at maximum effort. The highest HR reading at or near the finish is approximately your HRmax. Better yet, use a 3-week time trial protocol from a sports physiologist or use lactate threshold testing.
Five-zone model (widely used): Zone 1 (<60% HRmax) — recovery; Zone 2 (60–70%) — easy aerobic, fat-burning foundation; Zone 3 (70–80%) — aerobic tempo; Zone 4 (80–90%) — lactate threshold; Zone 5 (90–100%) — maximum effort, VO2max range. Most training volume should be in Zones 1–2 for aerobic base building.
The 80/20 principle (Seiler): elite endurance athletes spend roughly 80% of training time at low intensity (Zones 1–2) and 20% at moderate-high intensity (Zones 3–5). This ratio, counterintuitively, produces better adaptation than spending most time in Zone 3 ("gray zone" training).
See also: Pace Calculator · VO2max Estimator