Heart Rate Zone Calculator
This calculator is for informational purposes only and is not a substitute for professional medical advice. Consult a healthcare provider for personal health decisions.
Karvonen: Target HR = resting HR + (max HR − resting HR) × intensity
How Heart Rate Training Zones Work
Heart rate training zones divide exercise intensity into bands based on a percentage of your maximum heart rate (MHR). The simplest MHR estimate is 220 − age, though individual variation can be ±10–12 bpm. A 35-year-old would have an estimated MHR of 220 − 35 = 185 bpm. Zones are then calculated as percentage ranges of that maximum — each zone emphasizes different energy systems and training adaptations.
The five-zone model commonly used: Zone 1 (50–60% MHR) is very light recovery. Zone 2 (60–70%) builds aerobic base and fat oxidation. Zone 3 (70–80%) is moderate aerobic training. Zone 4 (80–90%) is threshold and lactate tolerance work. Zone 5 (90–100%) is maximum effort for short intervals. For our 35-year-old (MHR 185): Zone 2 spans 60–70% → 111–130 bpm; Zone 4 spans 80–90% → 148–167 bpm.
Zone 2 training has gained attention for cardiovascular health and fat metabolism — you should be able to hold a conversation with slight breathlessness. Zone 4 intervals improve lactate clearance and race pace for runners and cyclists. Most recreational athletes benefit from spending 70–80% of cardio time in Zones 1–2 and 10–20% in Zones 4–5, following an 80/20 polarized model.
The 220 − age formula is a population average. The Tanaka formula (208 − 0.7 × age) may be more accurate for older adults: a 50-year-old gets 208 − 35 = 173 bpm versus 170 bpm from 220 − age. Wearable devices that detect MHR during all-out efforts provide personalized data superior to any age formula. Resting heart rate and heart rate recovery after exercise are also valuable fitness indicators.
Enter your age to see estimated maximum heart rate and the bpm boundaries for each training zone. Use a chest strap or optical wrist sensor during workouts to stay in your target zone, adjusting pace or resistance to keep heart rate within the desired band.
Examples
| Example | Result |
|---|---|
| Age 30, MHR 190 | Zone 2: 114–133 bpm, Zone 4: 152–171 bpm |
| Age 25, MHR 195 | Zone 2: 117–137 bpm, Zone 4: 156–176 bpm |
| Age 40, MHR 180 | Zone 2: 108–126 bpm, Zone 4: 144–162 bpm |
| Age 50, MHR 170 | Zone 2: 102–119 bpm, Zone 4: 136–153 bpm |
| Age 35, MHR 185 | Zone 2: 111–130 bpm, Zone 4: 148–167 bpm |
| Age 45, MHR 175 | Zone 2: 105–123 bpm, Zone 4: 140–158 bpm |
| Age 20, MHR 200 | Zone 2: 120–140 bpm, Zone 4: 160–180 bpm |
Frequently asked questions
Zone 2 (roughly 60–70% of max heart rate) maximizes fat oxidation percentage, though higher zones burn more total calories per minute.
It estimates population averages with about ±10–12 bpm error. Individual max heart rate varies with fitness, genetics, and medications.
Most endurance athletes spend the majority of training time in Zones 1–2 for aerobic base, with 1–2 weekly sessions in Zones 4–5 for intensity.