Target Heart Rate Zone Calculator
Using the Karvonen method, your target zones are based on your heart rate reserve — the gap between your estimated max heart rate (220 minus your age) and your resting heart rate.
Warm-up
50–60% of heart rate reserve
128–140 bpm
Fat burn
60–70% of heart rate reserve
140–153 bpm
Aerobic
70–80% of heart rate reserve
153–165 bpm
Anaerobic
80–90% of heart rate reserve
165–178 bpm
Max effort
90–100% of heart rate reserve
178–190 bpm
Show the math
- 1
Estimate your maximum heart rate
220 − 30 = 190 bpm
A widely used (approximate) estimate of the fastest your heart should beat during exercise.
= 190 bpm
Read the steps as text
- Estimate your maximum heart rate. 220 − 30 = 190 bpm A widely used (approximate) estimate of the fastest your heart should beat during exercise.
- Find your heart rate reserve. 190 − 65 = 125 bpm The Karvonen method uses the gap between max and resting heart rate, which reflects your fitness level rather than just age.
- Scale by each zone's intensity, then add resting heart rate back. (125 × %) + 65 Each zone's low and high bpm come from this formula at that zone's percentage range.
Why heart rate reserve instead of a flat percentage
A simpler, older method just takes a percentage of your estimated max heart rate (220 minus age). The Karvonen method used here instead uses your heart rate reserve — the gap between max and resting heart rate — which better reflects individual fitness. Two people the same age with different resting heart rates (often lower in fitter people) get meaningfully different target zones.
Your resting heart rate is most accurate measured first thing in the morning, before getting out of bed, over a few days to get a stable average.
What each zone is for
Warm-up and fat-burn zones (50–70% of reserve) are sustainable for long periods and build an aerobic base. The aerobic zone (70–80%) is where most cardiovascular fitness training happens. Anaerobic (80–90%) and max effort (90–100%) zones can only be sustained briefly and are used for high-intensity interval training.
220 minus age is a widely used but approximate estimate of max heart rate — individual max heart rate can vary by 10–20 beats from this formula, so treat the resulting zones as a training guide rather than an exact physiological limit.
Frequently asked questions
- What is the Karvonen method?
- A way of calculating target heart rate zones using heart rate reserve (max heart rate minus resting heart rate) rather than a flat percentage of max heart rate alone, which better reflects individual fitness.
- How do I find my resting heart rate?
- Measure your pulse for a full minute right after waking up, before getting out of bed, ideally averaged over a few days for a stable number.
- How accurate is 220 minus age for max heart rate?
- It's a population average with a fairly wide margin of error — real max heart rate can differ from this estimate by 10–20 beats per minute for a given age. Treat the zones as a useful guide, not an exact limit.