Heart Rate Zones Calculator
Calculate your five heart rate training zones to train smarter — whether you're burning fat, building aerobic fitness, or pushing your VO2max.
What are Heart Rate Training Zones?
Heart rate training zones are ranges of heart rate — expressed as a percentage of your maximum heart rate — that correspond to different intensities of exercise and different physiological adaptations. By training within specific zones, you can target fat burning, aerobic endurance, lactate threshold, or VO2max development more precisely.
The most common model divides exercise intensity into five zones: Zone 1 (very light, recovery), Zone 2 (fat burning, aerobic base), Zone 3 (aerobic endurance, moderate effort), Zone 4 (lactate threshold, tempo effort), and Zone 5 (maximal effort, VO2max training).
The Karvonen method, which uses heart rate reserve (max HR − resting HR), provides more personalised zones than simple max HR percentages. If you know your resting heart rate, enter it above to use this more accurate method.
The 5 Heart Rate Training Zones
| Zone | % Max HR | Name | Training Benefit | Perceived Effort |
|---|---|---|---|---|
| Zone 1 | 50–60% | Recovery | Active recovery, light aerobic base | Very easy |
| Zone 2 | 60–70% | Aerobic / Fat Burn | Fat oxidation, aerobic endurance base | Easy, conversational |
| Zone 3 | 70–80% | Aerobic Endurance | Cardiovascular efficiency, aerobic capacity | Moderate |
| Zone 4 | 80–90% | Lactate Threshold | Raises lactate threshold, race pace fitness | Hard, breathing heavy |
| Zone 5 | 90–100% | VO2max | Max aerobic capacity, speed | Maximum effort |
Worked Examples
Example 1: 35-year-old, no resting HR measurement.
Estimated max HR = 220 − 35 = 185 bpm. Zone 2 = 60–70% × 185 = 111–130 bpm. Zone 4 = 80–90% × 185 = 148–167 bpm.
Example 2: Karvonen method, max HR 185, resting HR 55.
HRR = 185 − 55 = 130. Zone 2 = 55 + (0.60–0.70 × 130) = 55 + 78–91 = 133–146 bpm. These zones are higher than the simple % method, reflecting the person's fitness level.
Example 3: Athlete with measured max HR 195 bpm.
Zone 5 = 90–100% × 195 = 176–195 bpm. Used during interval training to develop VO2max.
Frequently Asked Questions
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The most accurate way is a maximal effort test: after a thorough warm-up, run hard uphill for 2 minutes at maximum effort, rest briefly, then repeat. Your peak heart rate reading is your max HR. The common formula 220 − age is a population average with a standard deviation of about ±10–15 bpm — your actual max could be meaningfully different.
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Zone 2 training (60–70% max HR) is low-intensity, steady-state aerobic exercise. It primarily trains the aerobic energy system and mitochondrial density, forming the foundation of aerobic fitness. High-volume Zone 2 training is associated with improved fat oxidation, cardiovascular efficiency, and endurance performance. Many coaches recommend 80% of total training volume in Zone 2.
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Yes, for most people. The Karvonen formula uses heart rate reserve (HRR = max HR − resting HR) to account for individual fitness level. A fit person with a low resting heart rate will have higher zone targets compared to a sedentary person with the same max HR. This makes zones more personalised and accurate.
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Not very. The 220 − age formula has a standard deviation of approximately ±10–15 bpm. This means for a 40-year-old, the formula predicts 180 bpm, but the true value could range from 165–195 bpm. Use it as a rough starting point, not a precise value. Alternatives like Tanaka (208 − 0.7 × age) are slightly more accurate for older adults.
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Not necessarily every session. Most training plans prescribe an 80/20 distribution: about 80% of volume in Zones 1–2 (easy effort) and 20% in Zones 4–5 (hard effort). Zone 3 ("the grey zone") is often avoided by endurance athletes as it is too hard to provide sufficient recovery and not intense enough to maximise high-end adaptations.