Heart Rate Zones Calculator
Calculate your five training heart rate zones based on age or max heart rate.
Optimize cardio, fat burn, and endurance training.
How Heart Rate Training Zones Work
Heart rate zones are percentage ranges of your maximum heart rate (MHR). Training at different intensities produces different physiological adaptations — from fat burning at low intensities to speed and VO2max development at high intensities.
Maximum heart rate estimation:
The most widely used formula (Tanaka, 2001):
MHR = 208 − (0.7 × Age)
The older Fox formula (220 − Age) is less accurate for older athletes. The Tanaka formula is preferred.
Worked example: 38-year-old runner:
MHR = 208 − (0.7 × 38) = 208 − 26.6 = 181 bpm
The 5 training zones:
| Zone | % of MHR | bpm (181 MHR) | Purpose |
|---|---|---|---|
| Zone 1 | 50–60% | 91–109 | Recovery, easy walking |
| Zone 2 | 60–70% | 109–127 | Fat burning, aerobic base |
| Zone 3 | 70–80% | 127–145 | Aerobic conditioning |
| Zone 4 | 80–90% | 145–163 | Lactate threshold, race pace |
| Zone 5 | 90–100% | 163–181 | VO2max, maximum effort |
Key training principles:
- Zone 2 is where most training volume should occur (60–80% of weekly mileage), it builds aerobic capacity with minimal injury risk
- Zone 4 is where 10K and half-marathon race pace typically falls
- Zone 5 intervals (30 sec to 4 min) are used sparingly to increase maximum oxygen uptake
Heart rate reserve method (Karvonen: more precise):
Target HR = ((MHR − Resting HR) × Zone%) + Resting HR
For a person with resting HR of 55 bpm targeting Zone 3 at 70%:
Target HR = ((181 − 55) × 0.70) + 55 = 88.2 + 55 = 143 bpm
Use a chest strap monitor for accuracy — wrist optical sensors can lag by 10–15 seconds during interval training.