Your daily water requirement isn’t one-size-fits-all. This hydration calculator uses your weight and activity level to estimate the optimal amount of water you need to stay hydrated, support metabolism, and maintain energy. Even mild dehydration can cause fatigue, headaches, and poor concentration — so knowing your number is essential for everyday health.
Most guidelines suggest a baseline of 30–40 ml per kg of body weight, then add extra fluid for physical activity. Our water intake calculator does exactly that: it adjusts for how often you exercise, because active bodies lose more water through sweat and need replenishment. Whether you're an athlete or mostly sedentary, this tool helps you keep your hydration on track.
Use this daily water requirement calculator as a simple starting point. Individual needs may vary due to climate, pregnancy, or illness — listen to your body. And remember, water from fruits, vegetables, and other beverages also counts toward your total. Stay hydrated, stay sharp.