Water Intake Calculator
Calculate how much water you should drink daily based on your weight, activity level, climate, and health goals.
About this tool
Calculate your optimal daily water intake using your body weight, activity level, exercise minutes, climate, and fitness goal. Includes per-meal breakdown and a visual glass tracker.
How to use it
Quick steps to get the most out of this utility.
- 1
Enter your body weight
Use the toggle to switch between kilograms and pounds, then enter your weight.
- 2
Set your activity level
Choose the option that best matches your daily activity from sedentary through to athlete.
- 3
Add exercise and climate
Enter your daily exercise minutes and select your typical climate.
- 4
Choose your goal
Select maintain, lose weight, or gain muscle to adjust your target accordingly.
- 5
Review your results
See your daily target in mL and cups, per-meal breakdown, and the glass tracker.
Why hydration matters
Water is essential for virtually every bodily function — from regulating temperature and transporting nutrients to lubricating joints and supporting cognitive performance. Even mild dehydration can impair concentration, increase fatigue, and affect mood.
While the classic "8 glasses a day" rule is a useful starting point, individual needs vary considerably. Athletes, people in hot climates, those with higher body weight, and people pursuing fat loss or muscle gain typically need more than the average person. This calculator adjusts for those variables to give you a more personalised target.
Drinking water throughout the day — rather than all at once — supports better absorption. Spreading intake across 4 meals is a practical strategy to hit your target without overwhelming your digestive system.
Frequently asked questions
How much water should I drink per day?+
A common recommendation is 30–35 mL per kg of body weight. For a 70 kg adult, that works out to roughly 2.1–2.5 litres per day. Your exact needs depend on activity level, climate, and health goals.
How does exercise affect water needs?+
Plan to add 250–500 mL of water for every 30 minutes of exercise, depending on intensity. Sweating during physical activity increases fluid loss, so athletes and highly active people often need significantly more than sedentary individuals.
Does hot weather increase how much water I should drink?+
Yes. In hot climates your body loses water through perspiration to regulate temperature. An extra 250 mL per day is a typical adjustment for hot environments, though very hot or humid conditions may require more.
Does water intake change if I am trying to lose or gain weight?+
Weight-loss goals often increase water needs by about 20%, as adequate hydration supports metabolism and helps the body utilise fat for energy. Muscle-gain goals typically add about 15%, since building muscle tissue requires water.
How many cups of water should I drink per meal?+
Dividing your daily target by 4 gives a rough per-meal guide. For a 2 400 mL daily target, that is about 600 mL per meal — roughly 2.5 standard 8 oz cups.
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