HEALTH · TARGET HEART RATE
Target Heart Rate Calculator
Find your aerobic training zones using the Karvonen heart rate reserve method. Shows five intensity zones from light to maximal, with Fox and Tanaka max-HR options.
About This Calculator
Training at the right intensity matters. Too easy and you don't stress your cardiovascular system enough; too hard and you risk injury or overtraining. The Karvonen method personalises your zones by factoring in your resting heart rate — not just your age.
How It Works
Enter your age and resting heart rate (measured lying down, upon waking). The calculator estimates your maximum heart rate using the Fox (220 − age) or Tanaka (208 − 0.7 × age) formula, then applies the Karvonen heart rate reserve method to map five intensity zones. If you have a measured maximum heart rate from a supervised fitness test, enter it to override the formula estimate.
The Formula
THR = (HRmax − HRrest) × intensity + HRrest
- HRmax
- estimated or measured maximum heart rate
- HRrest
- resting heart rate (bpm)
- intensity
- target intensity as a decimal (0.60 = 60%)
Frequently Asked Questions
- Why use resting heart rate in the calculation?
- The Karvonen formula accounts for your cardiovascular fitness. Two people with the same age and max HR but different resting HRs will have different heart rate reserves — and therefore different zones. A trained athlete with a low resting HR gets a wider usable range than a sedentary person.
- What is the aerobic zone?
- The aerobic zone (moderate to vigorous, roughly 60–84% HRR in the Karvonen method) is where sustained cardio training improves cardiovascular fitness and burns fat as a primary fuel. AHA recommends 150 minutes per week in this range for general health.
- Should I use Fox or Tanaka?
- Fox (220 − age) is the most widely recognised formula and a reasonable default. Tanaka (208 − 0.7 × age) has lower statistical error for fit adults, particularly at older ages. If you have a measured max HR from a graded exercise test, use that override instead.