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Water Intake Calculator
A personalized daily hydration target based on your body, activity and climate.
Enter your weight to get a personalized hydration target.
Formula
Daily intake ≈ weight (kg) × 35 ml, plus extra for exercise and heat
How to calculate
- 1Multiply your body weight in kg by 35 ml for a baseline.
- 2Add about 500 ml per hour of exercise.
- 3Add more for hot climates, high altitude or breastfeeding.
- 4Spread the total across the day rather than drinking it all at once.
How to use this calculator
- 1Enter your weight and typical activity level.
- 2Adjust for climate or exercise if relevant.
- 3See your personalized daily hydration target.
- 4Use the reminder schedule to pace intake through the day.
Examples
Baseline
A 70 kg person needs about 2.5 litres a day before exercise adjustments.
Training day
The same person with an hour of training targets roughly 3 litres total.
Common questions
Does coffee or tea count?
Yes — despite mild diuretic effects, caffeinated drinks still contribute net fluid to your daily total.
Can I drink too much water?
Rarely, but extreme intake in a short window can dilute blood sodium. Spread intake through the day and drink to thirst.
Do I need exactly this amount?
No — it is a target, not a rule. Thirst, urine color and how you feel are better day-to-day signals.
