How much water should I drink per day?

General guidelines suggest 35ml per kg of body weight per day. This increases with exercise, hot climates, pregnancy, and breastfeeding. The "8 glasses a day" rule is a rough average.

Does coffee and tea count as water intake?

Yes, most beverages including coffee and tea contribute to daily fluid intake. Only high-alcohol drinks are net dehydrating. However, plain water is always the healthiest choice.

Water Intake Calculator

Calculate your ideal daily water intake based on weight, activity level, climate, and life stage.

Units

Metric

Imperial

Sex

Male

Female

Weight (kg)

Age (years)

Exercise level

Climate

2.8 L

2,800 ml · 95 fl oz · ~11 glasses (250ml)

Breakdown

Base (body weight)

2450 ml

Exercise

350 ml

Water Intake Calculator

Your daily water needs depend on body weight, activity level, climate, and life stage. The Water Intake Calculator uses an evidence-based formula (35ml/kg/day base, adjusted for age) plus activity and environment additions.

General guidelines (EFSA / IOM)

Adult men: ~2.5 L/day total water intake
Adult women: ~2.0 L/day
Pregnant women: +300 ml/day
Breastfeeding: +500–700 ml/day

Signs of dehydration

Thirst, dark urine, headache, fatigue, and poor concentration. Urine should be pale yellow when well-hydrated.

Note on food water

About 20% of daily water comes from food. The calculator estimates total fluid intake from beverages; eating a fruit- and vegetable-rich diet reduces your drinking requirement.

General guidelines (EFSA / IOM)

Adult men: ~2.5 L/day total water intake
Adult women: ~2.0 L/day
Pregnant women: +300 ml/day
Breastfeeding: +500–700 ml/day

Signs of dehydration

Thirst, dark urine, headache, fatigue, and poor concentration. Urine should be pale yellow when well-hydrated.

Note on food water

About 20% of daily water comes from food. The calculator estimates total fluid intake from beverages; eating a fruit- and vegetable-rich diet reduces your drinking requirement.