Target Heart Rate Calculator
Calculate your training heart rate zones using the Karvonen formula. Five zones from light recovery to maximum effort, based on age and resting heart rate.
Inputs
Measure first thing in the morning.
Estimated max HR
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Zone 1 — Recovery (50-60% HRR)
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Zone 2 — Aerobic base (60-70%)
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Zone 3 — Aerobic (70-80%)
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Zone 4 — Threshold (80-90%)
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Zone 5 — Max effort (90-100%)
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About Target Heart Rate Calculator
Karvonen vs max%
Max%: simply maxHR × intensity. Karvonen uses Heart Rate Reserve (max − resting), which adjusts for fitness — fitter people with lower resting HR get shifted zones. Karvonen is generally more accurate.
220 − age limitation
A rough average. Real max HR varies ±10-15 bpm from this estimate. For accurate zones, do a max-HR field test (under supervision) or get a lab VO2max test.
Zone training applications
Zone 2 (aerobic base, ~70% HRR) builds endurance with minimal stress — most training time spent here. Zone 4 (threshold) builds lactate clearance. Zone 5 (intervals) raises VO2max. Periodize across zones for best results.