Karvonen Heart Rate Calculator
Find your target heart rate using heart-rate reserve.
Results update as you type.
This calculator provides estimates based on population research. Results are not medical advice. Consult a qualified healthcare provider before making health or nutrition decisions.
How it works
The Karvonen formula gives a more personalized training heart rate than a simple percentage of maximum, and this calculator applies it. You enter your age, resting heart rate, and desired intensity as a percentage, and it returns your target heart rate along with your estimated maximum heart rate and heart-rate reserve. The method works by first estimating your maximum heart rate as 220 minus your age, then subtracting your resting heart rate to get your heart-rate reserve, the range your heart can increase during exercise. It applies your chosen intensity to that reserve and adds your resting heart rate back. This is more individualized than taking a flat percentage of maximum heart rate, because it factors in your resting heart rate, which reflects your fitness: a fitter person with a lower resting rate gets a different, more appropriate target. Training in the right heart-rate zone helps you match effort to your goal, whether that is building endurance at moderate intensity, typically 60 to 70 percent, or improving fitness at higher intensities. For the most accurate resting heart rate, measure it first thing in the morning before getting up. Remember the 220-minus-age maximum is an estimate with individual variation, so treat the target as a guide and listen to your body. Enter your age, resting heart rate, and intensity to find your target.
Target HR = ((220 − age) − resting HR) × intensity% + resting HR
The Karvonen method uses heart-rate reserve, the difference between your maximum heart rate (estimated as 220 minus age) and your resting heart rate. It takes the chosen percentage of that reserve and adds your resting heart rate back, giving a target that accounts for individual fitness better than a plain percentage of maximum heart rate.
Source:Karvonen heart-rate reserve method
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter age, resting heart rate and target intensity.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Target heart rate updates instantly as you type — no button to press.
Frequently asked questions
What is the Karvonen formula?
The Karvonen formula calculates a target training heart rate using heart-rate reserve, the gap between your maximum and resting heart rates. It applies your chosen intensity percentage to that reserve and adds back your resting heart rate. This produces a more personalized target than simply taking a percentage of maximum heart rate, because it accounts for your resting rate and fitness.
Why is the Karvonen method better than percentage of max?
Taking a flat percentage of maximum heart rate ignores your resting heart rate, which reflects fitness. The Karvonen method uses heart-rate reserve, so a fitter person with a lower resting rate gets a target suited to them. This makes training zones more individualized and the prescribed intensity more accurate for people at different fitness levels.
How do I measure my resting heart rate?
Measure it first thing in the morning before getting out of bed, when you are fully rested. Count your pulse for 60 seconds, or use a heart-rate monitor or fitness tracker. Taking the average over several mornings gives the most reliable figure. A lower resting heart rate generally indicates better cardiovascular fitness.
What intensity should I train at?
It depends on your goal. Moderate intensity around 60 to 70 percent of heart-rate reserve builds aerobic endurance and is sustainable for longer sessions, while higher intensities of 70 to 85 percent improve cardiovascular fitness and speed. Beginners should start lower and build up. Mixing intensities across the week is a common and effective approach.
Is the 220-minus-age maximum accurate?
It is a widely used estimate but has significant individual variation, often plus or minus 10 to 12 beats per minute. Your true maximum may differ, so treat any target based on it as a guide rather than a precise number. For greater accuracy, a supervised maximal exercise test can measure your actual maximum heart rate.