Heart Rate Reserve Zones Calculator
Build five personalised training zones from your max and resting heart rate using the Karvonen heart-rate-reserve method.
How it works
HRR = max HR − resting HR · Target HR = resting HR + (%intensity × HRR) (Karvonen)
The Karvonen method scales zones by your heart-rate reserve — the gap between resting and maximum — instead of a flat percentage of max. Because it factors in resting heart rate, it individualises the zones to your fitness: a fitter athlete with a lower resting pulse gets a wider, more accurate range. Zones are guides to effort, not hard limits.
Worked example
Max 190, resting 60 gives HRR = 130. The bottom of Zone 2 (60%) is 60 + 0.60 × 130 = 138 bpm; the top (70%) is 60 + 0.70 × 130 = 151 bpm. So easy aerobic running sits around 138–151 bpm.
Frequently asked questions
How is this different from % of max heart rate?
The simple method takes a flat percentage of max HR and ignores your resting pulse. Karvonen adds resting HR back in, so two runners with the same max but different fitness get different — and more personal — zone boundaries.
How do I find my maximum heart rate?
The most accurate way is a supervised max test or the highest value seen in a hard race. Age formulas like 208 − 0.7 × age are only rough estimates and can be off by 10–20 bpm.
Where should most easy training sit?
For endurance athletes the bulk of weekly volume belongs in Zones 1–2. Spending too long in Zone 3 — the "grey zone" — is a common way to accumulate fatigue without the benefits of true easy or hard work.
Related calculators
Heart-rate and body-weight estimates are educational, based on population formulas — confirm with a coach or clinician before hard training, especially if you have any cardiac risk.