Target Heart Rate Calculator

Training heart rate zones from age and resting heart rate (Karvonen method)

Training heart rate zones calculated via the Karvonen method use both age and resting heart rate together, rather than age alone — a meaningfully more personalized approach than the simpler age-only formulas that are still commonly seen, since resting heart rate captures individual fitness-level differences that a pure age-based calculation misses entirely.

Why the Karvonen method is more personalized than age-only formulas

The simplest, most commonly cited heart rate zone method uses only age to estimate maximum heart rate, then applies flat percentages of that maximum to define training zones — this ignores individual fitness differences entirely, treating two people of the same age as needing identical training zones regardless of their actual cardiovascular fitness level. The Karvonen method instead incorporates resting heart rate into the calculation (using heart rate reserve — the gap between maximum and resting heart rate — rather than maximum heart rate alone), which means two people of the same age but different fitness levels (and correspondingly different resting heart rates) get different, more individually appropriate target zones, since a fitter person's lower resting heart rate genuinely changes what "70% intensity," for instance, should mean for their own cardiovascular system.

A worked example

Two people of identical age but different resting heart rates (one considerably fitter, with a lower resting rate) will get different Karvonen-calculated target zones for the same nominal training intensity — the age-only method would assign them identical zones despite their different fitness levels, while the Karvonen method's inclusion of resting heart rate captures that real physiological difference.

How this connects to your other health and fitness calculations

Target heart rate zones are commonly used alongside broader fitness tracking — for calorie expenditure during the same training sessions these zones are meant to guide, the Calories Burned Calculator uses activity intensity (which correlates with heart rate zone) as part of its own MET-based estimate.

Common mistakes

Using a simple age-only maximum-heart-rate formula and assuming it's equivalent to a properly individualized Karvonen calculation is a common oversimplification — the age-only method ignores resting heart rate entirely, which means it can meaningfully misrepresent appropriate training intensity for anyone whose fitness level (and resting heart rate) differs substantially from an untrained baseline.