Heart Rate Zone Calculator

The standard estimate, 220 minus your age, comes from the Fox formula, developed in the 1970s, and while it's still the most widely used baseline, it carries a real margin of error, roughly plus or minus 10 to 12 beats per minute for any individual. Factoring in your resting heart rate through a more refined calculation, the Karvonen method, tightens that estimate meaningfully by accounting for your actual current fitness level rather than age alone.

Each zone serves a genuinely different training purpose rather than just being "harder" or "easier" versions of the same thing. The lower zones burn a higher percentage of calories from fat specifically, while the upper zones burn more total calories and build anaerobic capacity, which is why a well-structured training week usually spends time in more than one zone rather than always pushing for maximum effort.

Enter your age, and your resting heart rate if you know it for a more precise result. The calculator outputs your estimated maximum heart rate along with clear boundaries for warm-up, fat-burn, aerobic cardio, and peak performance zones.

The most practical way to actually train within these zones in real time is a chest strap monitor or a fitness watch, since checking your pulse manually mid-workout isn't realistic for sustained effort. Alternating between zones within a single session, interval training, is a well-established way to build cardiovascular capacity efficiently. Your personal stats stay entirely private, calculated locally.