Heart rate zones calculator (Karvonen)
It sets the heart rate range for each training intensity, from very light to maximum, so you train at the effort you want.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter age, resting heart rate and max heart rate, if known.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Heart rate reserve = max HR − resting HR. Zone HR = reserve × intensity + resting HR. Max HR = 220 − age unless you enter it.
Example
Inputs: Age = 40 years, Resting heart rate = 65 bpm. Result: Zone 2 (fat burn): 134-146 bpm; Max heart rate used: 180 bpm; Heart rate reserve: 115 bpm.
Limits and caveats
- The 220 − age estimate can be off by 10 bpm or more; a measured max heart rate is more accurate.
- Some medicines such as beta blockers change heart rate, so check with your doctor.
Questions about this tool
What is the Karvonen method?
It sets intensity from heart rate reserve, the gap between max and resting heart rate, so it reflects your fitness better than percent of max alone.
How do I measure resting heart rate?
Count your pulse for 60 seconds in the morning after waking, before getting up, and average three days.
What is the fat burn zone?
Zone 2, 60% to 70% of heart rate reserve, where the body draws a larger share of energy from fat, though total calories are higher at harder efforts.