Calculate your target heart rate zones for exercise using the Karvonen method with heart rate reserve.
The Karvonen formula is a smarter way to set your target heart rate for exercise. Instead of working only from your maximum heart rate, it factors in your resting heart rate, which reflects your fitness, to personalize your training zones. This calculator uses your age and resting heart rate to work out the heart rate ranges that match different exercise intensities, so your cardio training can be both effective and appropriately challenging.
I like the Karvonen method because it respects individual differences. Two people the same age can have very different fitness levels, and accounting for resting heart rate makes the target zones genuinely personal rather than one-size-fits-all.
The Karvonen formula is built around your heart rate reserve, which is the gap between your maximum heart rate and your resting heart rate. A fitter person tends to have a lower resting heart rate, so their reserve is larger, and training zones calculated from that reserve reflect their actual capacity. By using the reserve rather than max heart rate alone, the method gives target zones that suit your fitness, not just your age.
First your maximum heart rate is estimated (commonly as 220 minus your age, a rough but widely used figure). Your heart rate reserve is the maximum minus your resting heart rate. The target for a given intensity is then your resting heart rate plus that percentage of your reserve. The calculator does this for you across the usual intensity bands, so you get a ready set of zones to train in.
Different intensities serve different goals. Lower zones (around 50 to 70 percent of reserve) suit easy, fat-burning and base-building efforts you can sustain comfortably. Moderate zones (around 70 to 85 percent) build aerobic fitness. Higher zones push your limits for shorter intervals. A good training plan mixes these, with most time spent easier than people expect, which is where the Karvonen zones help you stay honest about intensity.
Because the formula depends on it, measure your resting heart rate properly: take it first thing in the morning before getting up, ideally over several days, and average it. A fitness tracker can help. Also remember the 220-minus-age maximum is an estimate that varies between individuals, so treat the zones as a well-informed guide and listen to your body and breathing alongside the numbers.
This calculator uses established, peer-reviewed formulas and reference ranges from recognized health and nutrition authorities. Results are estimates for general education, not a medical diagnosis. For decisions about your health, consult a qualified clinician. Reviewed by Jennifer Zoned, PhD, Nutrition Researcher.
It is a method for setting personalized exercise heart rate zones that factors in your resting heart rate, not just your maximum. It uses your heart rate reserve (maximum minus resting), so the resulting target zones reflect your fitness level rather than being based on age alone.
Because it accounts for your fitness through your resting heart rate. Two people the same age can have very different fitness, and a fitter person has a lower resting heart rate and larger reserve. Using the reserve makes the target zones genuinely personal rather than one-size-fits-all.
Take it first thing in the morning before getting up, ideally over several days, and average the readings. A fitness tracker can help. An accurate resting heart rate matters because the whole calculation depends on it.
It depends on your goal. Easy, sustainable efforts sit around 50 to 70 percent of your reserve, aerobic fitness builds around 70 to 85 percent, and higher zones are for shorter intervals. A good plan mixes these, with most time spent easier than many people expect.
