Heart Rate Calculator: Training Zones and Maximum Heart Rate
Training by heart rate keeps each session at the intensity it is meant to be. This calculator estimates your maximum heart rate from age and then splits it into zones, so easy runs stay easy and hard intervals are genuinely hard.
The five training zones
- Zone 1, 50-60% of max — recovery and warm-up.
- Zone 2, 60-70% — aerobic base and fat metabolism; where most endurance volume belongs.
- Zone 3, 70-80% — tempo work, improves aerobic capacity.
- Zone 4, 80-90% — threshold intervals, raises lactate tolerance.
- Zone 5, 90-100% — short maximal efforts, improves VO2 max and speed.
Estimating maximum heart rate
The familiar 220 minus age formula is easy but carries a standard deviation of 10-12 beats per minute. The Tanaka formula, 208 − (0.7 × age), fits older adults better. The Karvonen method uses your resting heart rate as well and gives more personal zones. A supervised graded exercise test is the only genuinely accurate way to find your true maximum.
Building a weekly balance
Endurance athletes commonly follow a polarised pattern: around 80% of training in zones 1-2 and 20% in zones 4-5, with little time in the middle. Beginners should build several weeks of easy aerobic work before adding intervals. Resting heart rate is also worth tracking — a sustained rise of five to ten beats often signals fatigue or illness.
Key takeaways — Heart Rate Calculator
- Zones are percentages of maximum heart rate; estimates carry ±10 bpm of error.
- Most training volume should sit in the easy aerobic zone.
- Get medical clearance before high-intensity work if you have cardiac risk factors.