# Karvonen Formula

The Karvonen Formula is a mathematical formula that helps you determine your target heart rate (HR) training zone. The formula uses maximum and resting heart rate with the desired training intensity to get a target heart rate.

Target Heart Rate = ((max HR − resting HR) × %Intensity) + resting HR example

Ideally, you should measure your resting and maximum heart rate for more accurate results. If the maximum heart rate cannot be measured directly, it can be roughly estimated using the traditional formula 220 minus your age (see this table of heart rate max). Also, an average value of 70 bpm can be used for resting heart rate if it is not known. See also Resting Heart Rate, and this guide to measuring heart rate.

## Example Training Heart Rate Zone

For example, for a 25 yr old who has a resting heart rate of 65, wanting to know his training heart rate for the intensity level 60% - 70%.

His Minimum Training Heart Rate:
220 - 25 (Age) = 195
195 - 65 (Rest. HR) = 130
130 x .60 (Min. Intensity) + 65 (Rest. HR) = 143 Beats/Minute

His Maximum Training Heart Rate:
220 - 25 (Age) = 195
195 - 65 (Rest. HR) = 130
130 x .70 (Max. Intensity) + 65 (Rest. HR) = 156 Beats/Minute

His training heart rate zone will therefore be 143-156 beats per minute.