Health

💧 Water Intake Calculator

Get a personalized daily water goal based on your body weight, how much you exercise, and how hot your climate is — shown in litres, glasses and bottles.

—Litres per day
—250 ml glasses
—500 ml bottles

Rule of thumb used: ~35 ml per kg of body weight, +350 ml per 30 min of exercise, + a climate adjustment. Food also supplies ~20% of your fluids. This is general guidance, not medical advice — kidney or heart conditions may require different limits.

About the Water Intake Calculator

Hydration needs are not one-size-fits-all: they scale with body mass, sweat losses from activity, and climate — which is why a one-line “8 glasses a day” rule fails desert dwellers and office workers alike.

This calculator starts from the widely used weight-based guideline (about 35 ml per kg), adds sweat replacement for exercise, and layers on a climate adjustment — then translates the result into glasses and bottles, the units people actually track. Water is only half of the intake picture, though; the calorie calculator covers the energy side with your BMR and daily calorie needs.

Frequently asked questions

How much water should I drink per day?

A common guideline is about 35 ml per kilogram of body weight — roughly 2.5 litres for a 70 kg adult — plus more for exercise and hot weather. Around 20% of your fluid intake normally comes from food.

Do coffee and tea count?

Yes. Despite their mild diuretic reputation, caffeinated drinks still hydrate you on balance. Water is still the cheapest and healthiest default.

Can I drink too much water?

Rarely, but yes — extreme intake in a short time can dilute blood sodium (hyponatremia). Spread intake across the day and drink to thirst, especially if you have kidney or heart conditions.

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