Free Tool
Karvonen Heart Rate Zone Calculator
Calculate personalized training zones using the Karvonen formula. Enter your age and resting heart rate for more accurate zone targets that account for your fitness level.
Used to estimate your max heart rate (220 - age)
Measure first thing in the morning before getting out of bed. Providing this enables the more accurate Karvonen formula.
What is the Karvonen method?
The Karvonen method (also called the heart rate reserve method) was developed by Finnish physiologist Martti Karvonen. Unlike the standard percentage-of-max-HR approach, it factors in your resting heart rate to calculate training zones. This makes zones more personalized because resting heart rate reflects individual fitness level: a well-trained athlete with a resting HR of 45 will get different zone targets than a beginner with a resting HR of 78, even if both are the same age.
The Karvonen formula
Heart Rate Reserve (HRR) = Max HR - Resting HR
Target HR = Resting HR + (intensity % x HRR)
For example, a 30-year-old with a resting HR of 60 has a max HR of 190 and an HRR of 130. Their Zone 2 (60-70%) would be 60 + (0.60 x 130) = 138 bpm to 60 + (0.70 x 130) = 151 bpm. Using the standard method, their Zone 2 would be 114-133 bpm, which is significantly lower and may feel too easy for someone with good fitness.
Why use Karvonen over the standard method?
The standard method assumes everyone of the same age has identical zone ranges, regardless of fitness. The Karvonen method addresses this by using heart rate reserve as the baseline. A fit person with a low resting HR gets higher zone targets, reflecting that they need to work harder to reach the same relative intensity. Research has shown that the Karvonen method correlates more closely with percentage of VO2 Max than the standard method, making it a more accurate guide for training intensity.
How to measure resting heart rate
Measure your resting heart rate first thing in the morning before getting out of bed. Lie still for a few minutes, then count your pulse for a full 60 seconds, or use a fitness tracker that records overnight resting HR. Take measurements over several days and use the average for the most reliable result. Avoid measuring after caffeine, alcohol, illness, or poor sleep, as these can temporarily elevate resting HR.
Just need a quick calculation?
If you do not know your resting heart rate, the standard method only requires your age and provides a good starting point for heart rate-based training.