Knowing your target heart rate zones is the key to smarter, more effective workouts. Whether your goal is fat burning, improving cardiovascular endurance, or pushing into high-intensity anaerobic training, each zone serves a distinct physiological purpose. This calculator uses your age and resting heart rate to pinpoint your personalized aerobic and anaerobic zones based on the Karvonen method — the gold standard used by fitness professionals. Stop guessing and start training with precision.