Water Intake Calculator — How Much Water Should You Drink?
Use this free water intake calculator to find out exactly how much water you should drink each day. Enter your weight, activity level, climate and age range to get a personalised daily water recommendation in litres, millilitres and fluid ounces — plus exactly how many glasses and bottles that equals.
Water Intake Calculator
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How to Use the Water Intake Calculator
Enter your weight and select your activity level, climate and age range. Click Calculate for your personalised daily water intake recommendation shown in multiple formats including glasses and bottle counts.
How Is Daily Water Intake Calculated?
The baseline recommendation is approximately 33ml of water per kilogram of bodyweight per day. This is then adjusted based on your activity level — more exercise means more fluid lost through sweat — your climate and your life stage. Pregnant and breastfeeding women have higher fluid requirements.
Signs You're Not Drinking Enough Water
Dark yellow urine is the clearest sign of dehydration. Other signs include headaches, fatigue, difficulty concentrating, dry mouth and feeling hungry when you’ve recently eaten. Mild dehydration of just 1-2% of bodyweight can noticeably impair physical and mental performance.
Tips to Drink More Water Each Day
Start every morning with a full glass of water before coffee or food. Carry a reusable bottle and set hourly reminders on your phone. Eat water-rich foods like cucumber, watermelon, lettuce and strawberries. Replace one sugary drink per day with water — this alone makes a significant difference over time.
FAQs
How much water should I drink per day?
The general guideline is approximately 33ml per kg of bodyweight per day. For a 70kg person that’s around 2.3 litres. Activity level, climate and age all affect this.
Does coffee and tea count toward daily water intake?
Yes — despite the mild diuretic effect of caffeine, coffee and tea still contribute to overall hydration. However water remains the best hydration source.
How do I know if I'm drinking enough water?
The simplest indicator is urine colour. Pale yellow means well hydrated. Dark yellow means drink more. Clear urine can indicate overhydration.
Can you drink too much water?
Yes — overhydration (hyponatremia) is possible but rare in healthy adults. It’s most common in endurance athletes who drink excessive amounts without electrolytes.
Does water intake affect weight loss?
Drinking water before meals can reduce appetite and calorie intake. Water has no calories and replacing sugary drinks with water supports weight loss significantly.