The Heart Rate Calculator helps determine your maximum heart rate and target exercise heart rate zone using your age and resting heart rate. The formula Maximum Heart Rate = 220 − Age estimates the highest heart rate your body can safely achieve during physical activity. The Target Zone is calculated as Resting Heart Rate + (Heart Rate Reserve × %Intensity), typically between 50% and 85% of your maximum effort. Staying within this zone ensures safe and effective workouts, improving endurance, cardiovascular health, and fat-burning efficiency.