← All ToolsDaily Water Intake Calculator – Hydration Goal Service | CalcTools
Calculate how much water you should drink daily based on your body weight and exercise habits. Stay hydrated for peak performance.
Water is the most essential nutrient for the human body, playing a key role in everything from brain function and energy levels to skin health and digestion. However, the old '8 glasses a day' rule is a myth—your actual needs depend heavily on your body size and how much you sweat during exercise. Dehydration can lead to fatigue, headaches, and decreased physical performance. Our Water Intake Calculator provides a personalized hydration target, ensuring you are drinking exactly what your body needs to stay at its best.
How it Works
The calculator uses a base requirement of approximately 33ml of water per kilogram of body weight. It then adds extra fluid to compensate for water lost during physical activity (approx. 350ml per 30 minutes of exercise).
Calculation Formula
(Weight × 0.033) + (Exercise_Min / 30 × 0.35)
Calculation Examples
1. **Average**: A 70kg person with no exercise needs **~2.3 Liters**.
2. **Athlete**: An 80kg person with 60 minutes of exercise needs **~3.3 Liters**.
Why use this tool in your daily life?
Hydration is the simplest way to boost your daily energy and cognitive performance. This tool ensures you aren't leaving your health to chance, giving you a clear, achievable daily goal to keep your body functioning at its peak.
Tip
Bookmark this tool for quick access. Everything runs locally in your browser.