Maximum heart rate is 220 minus your age
That's the most widely used estimate. Multiply it by an intensity percentage and you get five zones — the lower zones burn a higher share of fat as fuel, the higher zones build cardiovascular fitness and anaerobic capacity.
Adding your resting heart rate makes it more precise
If you enter your heart rate right after waking up (resting heart rate), this calculator switches to the Karvonen method, also called heart rate reserve. Since resting heart rate varies with fitness level, two people the same age with different fitness levels end up with different target zones — this method accounts for that.
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Frequently asked questions
QHow accurate is the 220 minus age formula?
It's a widely used estimate, not a precise measurement — individual variation can put your real maximum heart rate 10–15 beats above or below it. The only way to know your exact maximum is a supervised exercise stress test.
QWhich zone burns the most fat?
Lower zones (Zone 2, roughly 60–70%) burn a higher percentage of calories from fat, but total calories burned still increases with intensity. Weight loss depends more on total calories burned and diet than on any single zone.
QWhat's the difference between the Karvonen method and the simple method?
The simple method multiplies your maximum heart rate directly by the percentage. The Karvonen (heart rate reserve) method subtracts your resting heart rate first, applies the percentage to that reserve, then adds the resting heart rate back — producing a number that reflects your current fitness level.