Heart Rate Zone Calculator (Karvonen Method)
Enter your age and resting heart rate to see your target beats per minute for each of the five training zones.
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Formula
Maximum heart rate = 220 - ageHeart rate reserve = maximum heart rate - resting heart rateTarget heart rate = reserve x intensity + resting heart rate
Intensity runs from 50% to 100% in five zones of 10% each.
Worked example
Age 40, resting heart rate 60: maximum is 220 - 40 = 180 and reserve is 180 - 60 = 120.
- Zone 1 (50 to 60%): 120, 132
- Zone 2 (60 to 70%): 132, 144
- Zone 3 (70 to 80%): 144, 156
- Zone 4 (80 to 90%): 156, 168
- Zone 5 (90 to 100%): 168, 180
Frequently asked questions
What is the Karvonen formula?
Karvonen sets a target heart rate as resting heart rate plus a percentage of your heart rate reserve, which is maximum heart rate minus resting heart rate. At age 40 with a resting rate of 60, the reserve is 180 - 60 = 120 beats.
How is maximum heart rate estimated here?
This calculator uses 220 minus your age, so a 40 year old gets 180 beats per minute. It is a population average and individual maximums can differ by 10 or more beats.
What are the five heart rate zones?
Zones run from 50 to 100% of your reserve in 10% steps, from very light effort to maximum effort. With a reserve of 120 and a resting rate of 60, zone 2 (60 to 70%) is 132 to 144 beats per minute.
Why use resting heart rate instead of age alone?
Resting heart rate reflects your fitness. Two people of the same age with resting rates of 50 and 80 get different zones because the Karvonen method scales the zones to each person's reserve.