Find your personalised daily water target based on weight, activity level, and climate. Includes hydration tips and a tracker.
This tool uses the European Food Safety Authority (EFSA) base formula of 35 ml per kilogram of body weight per day as the starting point. This is then adjusted for activity level (exercise and physical labour significantly increase sweat losses), climate (hot weather increases insensible water losses through skin and respiration), and special physiological states (pregnancy and breastfeeding have well-documented increased requirements — the Indian Council of Medical Research recommends +300 ml/day during pregnancy and +500 ml/day during breastfeeding).
India's climate significantly elevates daily water requirements beyond global averages. During North Indian summers (May–June), temperatures regularly exceed 42°C in plains areas. At these temperatures, a sedentary individual loses 1–1.5 litres more water per day through sweat than in temperate conditions. Manual labourers and outdoor workers in Indian summers can lose 4–6 litres through sweat alone, requiring extraordinary hydration efforts. The most dangerous period is mid-afternoon (12 PM–3 PM) when the combination of peak temperature and solar radiation maximises sweat rate.
Mild (1–2% body weight): thirst, reduced urine output, slightly darker urine. Moderate (3–4%): headache, dizziness, reduced concentration, noticeably dark urine (amber colour). Severe (5%+): rapid heartbeat, confusion, inability to stand — requires immediate medical attention. The thirst sensation typically lags behind actual dehydration by 30–60 minutes, which is why waiting until you are thirsty before drinking is insufficient, especially during exercise or outdoor work in the heat.
The most practical daily hydration check: your urine should be pale yellow (straw-coloured). Clear and colourless means over-hydration. Dark yellow to amber means mild dehydration — drink water immediately. Orange or brown signals severe dehydration or possible medical issues — seek medical advice. The first morning urine is naturally darker; judge hydration by urine colour during the day after morning voiding.