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Water Intake Calculator Guide
Estimate how much water you might aim to drink each day based on your body weight and how much you exercise. It's a general starting point — real needs vary with climate, health, and diet.
A common guideline is about 35 ml of water per kg of body weight, plus extra for exercise — roughly 350–500 ml for every 30 minutes of activity.
How Much Water Should I Drink?
For a 70 kg (154 lb) person doing 30 minutes of exercise, that works out to roughly 2.9 liters, or about 12 cups. Much of your fluid also comes from food and other drinks, so listen to your thirst too.
Factors That Change Your Needs
Hot weather, high altitude, illness, pregnancy, and intense exercise all raise fluid needs. Dark urine can signal you need more, while pale-yellow usually means you're well hydrated. There's no need to force water beyond comfortable thirst.
This is a general estimate for information only, not medical or nutritional advice. Individual needs vary with health, goals, and other factors — talk to a doctor or registered dietitian for guidance specific to you.
Related: Calories Burned, BMR Calculator, and Protein Intake.
Frequently Asked Questions
How much water should I drink a day?
A rough guide is about 35 ml per kg of body weight plus extra for exercise, but needs vary by person and climate.
Does exercise increase water needs?
Yes — you lose fluid through sweat, so add roughly 350–500 ml for each 30 minutes of activity.
Does drinking count only from water?
No — other drinks and water-rich foods contribute to your total fluid intake.
Can I drink too much water?
Very rarely, drinking far too much in a short time can be harmful, so drink to thirst rather than forcing large amounts.
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