Heart Rate Zones Calculator
Calculate your training zones from max HR, LTHR, or HRR (Karvonen)
Inputs
Highest HR you've measured in a max-effort test, OR estimate via 208 − 0.7 × age (Tanaka 2001).
Your zones
Active recovery, warm-up, cool-down
Aerobic base — long, conversational rides and runs
Tempo / sweet-spot — comfortably hard
Just below threshold — lactate steady state
3–8 min intervals — top-end aerobic capacity
How these zones are computed
% of Max HR uses straight percentages of your peak heart rate. Easy to set up, but sensitive to how accurate your max HR estimate is.
LTHR (Friel) anchors the boundaries on lactate threshold heart rate — far more athlete-specific because it reflects metabolic, not just cardiac, capacity. Source: Joe Friel, The Cyclist's Training Bible (5th ed., 2018).
Karvonen / HRR uses heart-rate reserve (HRmax − HRrest) instead of raw HRmax, which adjusts for fitness (fitter athletes have lower resting HR). Karvonen 1957, Annales Medicinae Experimentalis et Biologiae Fenniae.
Heart-rate zones are a starting point, not gospel. Real metabolic-test zones can sit ±5 BPM from any of these models. Re-test 2–3 times a season as fitness changes.
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