Heart Rate Calculator
Calculate your max heart rate, training zones and VO2 max estimate
Fox formula: 220 − age. The most widely known formula, though it tends to overestimate for older adults.
// 5 Training Zones (% of Max HR)
// Check Any Heart Rate
// Karvonen Method (Heart Rate Reserve)
The Karvonen method uses your resting HR to give more personalised zones, accounting for individual fitness level.
// Max HR Formula Comparison
// VO2 Max Fitness Category
Understanding Heart Rate Training Zones
Heart rate training zones allow you to target specific physiological adaptations during exercise. Training at the right intensity for the right purpose is more effective than training hard all the time.
Formulas
The 5 Training Zones
Zone 1 — Recovery (50–60%): Very light effort. Used for warm-up, cool-down and active recovery. Improves basic endurance and fat metabolism.
Zone 2 — Aerobic (60–70%): Light to moderate effort. The most important zone for building aerobic base. Comfortable, conversational pace. Most of your training volume should be here.
Zone 3 — Tempo (70–80%): Moderate to hard. Improves aerobic capacity and efficiency. Somewhat uncomfortable but sustainable. Often overused by amateur athletes.
Zone 4 — Threshold (80–90%): Hard effort. Raises lactate threshold — the point at which lactic acid accumulates faster than it can be cleared. Used for interval training.
Zone 5 — VO2 Max (90–100%): Maximal effort. Improves maximum oxygen uptake. Only sustainable for short bursts. Used in sprint and high-intensity interval training.
What Is the Karvonen Method?
The Karvonen method calculates zones relative to your Heart Rate Reserve (max HR minus resting HR) rather than max HR alone. This produces more personalised zones because it accounts for individual fitness level — a fitter person with a lower resting HR will have higher target zones than a less fit person of the same age with the same max HR.
From the Blog
// 80/20 Rule
Elite endurance athletes spend ~80% of training in Zone 1–2 and only ~20% in Zones 3–5. Most amateurs do the opposite.
// Resting HR
Measure resting HR first thing in the morning before getting up. Under 60 bpm indicates good cardiovascular fitness.
// Zone 2 Benefits
Consistent Zone 2 training improves mitochondrial density and fat oxidation — the foundation of endurance performance.
// Overtraining
A resting HR 5–7 bpm higher than normal is an early sign of overtraining or illness. Take an easy day.