Understanding the Heart Rate Zone Calculator
Heart rate training zones let you match your effort to your goal, whether that is building endurance, burning fat, or boosting performance. This calculator uses the Karvonen method, which factors in your resting heart rate for more personalized zones than age-based formulas alone.
What the zones represent
Lower zones (around 50–70% of maximum) build aerobic base and are sustainable for long efforts; middle zones improve aerobic capacity; higher zones (80%+) develop speed and power but are tiring and should be used sparingly. Training across zones, rather than always pushing hard, produces the best long-term fitness gains.
Why resting heart rate matters
The Karvonen method uses your heart rate reserve — the gap between resting and maximum heart rate — to set zones tailored to your fitness. Fitter people tend to have lower resting heart rates, so this approach gives more accurate targets than formulas based on age alone. Measure your resting rate first thing in the morning for best results.
Tips & things to know
- •Most training should happen in lower, sustainable zones.
- •Measure resting heart rate when you first wake up.
- •Max heart rate estimates are rough — a field test is more accurate.