How target heart rate is calculated
This calculator shows two common target heart rate methods. The first is the Karvonen method, which uses heart rate reserve and resting heart rate. The second is the simpler method that uses a percentage of maximum heart rate.
Because Karvonen includes resting heart rate, it often produces a different target range than the simple percentage method, even when the same intensity is selected.
Core formulas
Max Heart Rate = 220 โ age
Heart Rate Reserve = max heart rate โ resting heart rate
Karvonen Target = (heart rate reserve ร intensity) + resting heart rate
Simple Target = max heart rate ร intensity
If you enter a measured max heart rate, the calculator uses that instead of the age-based estimate.
Karvonen vs simple max percentage
The simple method is straightforward because it only needs maximum heart rate. Karvonen adds resting heart rate into the calculation, which can shift the target range upward or downward depending on the individual.
That makes Karvonen a more personalized range when resting heart rate is known, while the simple method remains useful for quick estimates.
| Method |
Main Inputs |
What It Uses |
| Karvonen | Max HR, Resting HR, Intensity | Heart rate reserve |
| Simple % of Max | Max HR, Intensity | Percentage of max heart rate |
Why the displayed range can change
The displayed target range depends on the chosen method, the intensity range, the resting heart rate, and whether the calculator uses a measured maximum heart rate or an estimated one. That is why two people of the same age can still see different heart rate targets.
Preset ranges are included for convenience, but custom intensity inputs are also supported.
Frequently Asked Questions
What is heart rate reserve?+
Heart rate reserve is maximum heart rate minus resting heart rate. It is the value used in the Karvonen method to personalize the target range. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.
Why is Karvonen different from simple max percentage?+
Because Karvonen includes resting heart rate and the simple method does not. That means the same intensity percentage can produce different targets across the two methods. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.
Should I use measured max heart rate or estimated max heart rate?+
A measured maximum heart rate is usually more specific to the individual. An age-based estimate is still useful when a measured value is not available. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.
What intensity range should I choose?+
That depends on the training purpose. Lower ranges are generally used for easier work, while higher ranges are commonly used for harder efforts. This calculator provides presets to make that easier. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.
Are the results exact?+
No. They are structured estimates based on formulas and the inputs you provide. Device accuracy, measurement quality, and individual variation all matter. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.