The Hydration Calculator estimates your daily water intake based on your body weight and activity level. It uses the formula Water (mL) = Weight (kg) × 35 × Activity Factor, where 35 mL of water is recommended per kilogram of body weight, and the activity factor adjusts for how active you are during the day. This tool helps users maintain proper hydration for better metabolism, energy levels, and overall health. It’s especially useful for athletes, fitness enthusiasts, and anyone looking to improve their daily hydration routine.