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The Karvonen method starts from your estimated maximum heart rate (220 minus age), subtracts your resting heart rate to get your heart rate reserve, then builds each zone as resting rate plus reserve times an intensity percentage. Results are estimates for training guidance, not medical advice, individual maximums can differ from the formula by 10–15 bpm.
The Karvonen method uses your heart rate reserve, the gap between your maximum and your resting heart rate, instead of a plain percentage of maximum. First: max HR = 220 − age. Then: reserve = max HR − resting HR. Each zone target is resting HR + (reserve × intensity).
Worked example, age 35, resting 60 bpm: max HR = 185, reserve = 125. Zone 2 (60–70%): 60 + 125×0.60 to 60 + 125×0.70 = 135–148 bpm.
Because it starts from your resting rate, the same age gives different zones for a fit and an unfit person, which is why coaches prefer Karvonen over plain percentage-of-max charts.
Enter your age and your resting heart rate in beats per minute. Measure resting heart rate first thing in the morning, before getting out of bed, and average three mornings for a stable number.
Click Calculate to see your estimated maximum heart rate and all five training zones in bpm. Keep the zones on your watch or a note on your bike computer so every session has a target.
Zone 1 (50–60%) is recovery, easy warm-ups and cooldowns where you can chat freely. Zone 2 (60–70%) is the aerobic base and fat burn zone: conversational pace where most endurance volume should live.
Zone 3 (70–80%) is tempo: breathing hardens, speech becomes short phrases. Zone 4 (80–90%) is lactate threshold, the boundary between aerobic and anaerobic effort, hard and sustainable only for much shorter efforts. Zone 5 (90–100%) is VO2 max: all-out intervals of a few minutes.
The dominant endurance approach is the 80/20 rule: about 80% of training time in zones 1–2, 20% in zones 4–5. The classic mistake is living in zone 3, hard enough to tire you, not hard enough to adapt you.
Plain percentage-of-max charts ignore your fitness: 70% of a 185 max is 130 bpm for everyone. Karvonen gives that same 35-year-old resting at 70 a 70% target of 151 bpm, a 21 bpm difference that separates a walk from a workout.
As conditioning improves and resting heart rate falls, the reserve widens and Karvonen zones move with you; percentage charts never do. Alternative max formulas like Tanaka (208 − 0.7 × age) fit measured data better over 40, but any formula is an average, a supervised max test is the gold standard.
Lie still in the morning before sitting up, find your pulse at the wrist or neck, and count beats for a full 60 seconds, no caffeine, no stress, no recent exercise. Repeat on three calm mornings and take the average.
Typical resting rates run 60–80 bpm for most adults and 40–60 for trained endurance athletes. Note that beta blockers and some other medicines hold the pulse down, making every zone read too high, if you take them, ask your doctor which zones to use instead.
Zone 2 is 60–70% of your heart rate reserve by the Karvonen method, the conversational, fat-burning aerobic base zone. For a 35-year-old resting at 60 bpm it is about 135–148 bpm. Enter your own numbers above for your exact range.
The classic estimate is 220 minus your age; the Tanaka formula (208 − 0.7 × age) fits measured data better, especially over 40. Both are averages with about ±10 bpm of spread, a supervised exercise test gives your true maximum.
The Karvonen formula computes training zones from heart rate reserve: target = resting HR + (max HR − resting HR) × intensity. It personalises zones to your fitness because a lower resting rate widens the reserve and shifts every zone.
Roughly, it predicts the population average, but any individual's true maximum can sit 10–15 bpm above or below it. For running and cycling zones that is a meaningful error, so treat formula zones as estimates and cross-check with perceived effort.
First thing in the morning, before getting out of bed: find your wrist or neck pulse and count for 60 seconds. Avoid caffeine and exercise beforehand, and average three mornings. That number is the anchor of the whole Karvonen calculation.
Most endurance programmes follow the 80/20 rule: 80% of time easy in zones 1–2, 20% hard in zones 4–5. Zone 2 builds the aerobic base and fat adaptation; zones 4–5 build speed and threshold. Zone 3 is the trap, tiring without much adaptation.
Yes. Beta blockers and some other drugs lower heart rate, so formula-based zones sit too high and the talk test becomes more reliable. If you take heart or blood pressure medication, have a doctor or exercise physiologist set your zones.