Target Heart Rate Calculator (Karvonen)
Your training heart rate using the Karvonen heart-rate-reserve method.
Result
Target heart rate (bpm)
151
Max heart rate (bpm)
190
How it works
Training by heart rate keeps each workout at the intensity it is meant to have. This calculator uses the Karvonen method: your target heart rate = resting HR + (maximum HR − resting HR) × intensity. By working with your heart-rate reserve rather than raw maximum, it adapts to your personal physiology. Maximum heart rate is estimated as 220 minus your age unless you have a measured value; resting heart rate is best taken on waking. At 40 years old with a resting HR of 60, a 70% intensity gives 60 + (180 − 60) × 0.70 = 144 bpm. Typical zones: 50–60% of reserve for recovery, 60–70% for fat-burning and base endurance, 70–80% for aerobic fitness, 80–90% for threshold, and above 90% for short maximal efforts. If you take medication that affects heart rate (like beta-blockers), the estimates will not apply — go by feel or consult your doctor.
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Frequently asked questions
Why use resting heart rate?
It personalises the zone — two people the same age can have very different reserves.
What intensity should I pick?
50–70% for easy/fat-burning, 70–85% for endurance and tempo work.
Why use the Karvonen method instead of a simple percentage of max HR?
Because it accounts for your resting heart rate — a marker of your fitness. Two people with the same max HR but different resting rates get different, more personal training targets.
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