Water Intake Estimator

Rough daily fluid target based on body weight, adjusted for activity and hot climate.

Reviewed by Pooja V. Menon, Registered Dietitian · Last updated

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How this is calculated

For a healthy Indian adult, ICMR-NIN's Dietary Guidelines for Indians 2024 sets the day's fluid target at ~2 L (about eight glasses), including all beverages, rising in heat or with vigorous activity. NIN-DGI also flags carbonated drinks, sugarcane juice (13–15 g sugar / 100 ml), and packaged fruit juices as poor substitutes for plain water.

The estimate above uses the more granular clinical heuristic of 30–35 ml/kg body weight with activity and climate add-ons, which is useful for individualising a target around the NIN-DGI baseline. This agrees broadly with EFSA's adequate intake of 2.0 L/day for women and 2.5 L/day for men and the US National Academies' 2.7 L / 3.7 L figures, which include all sources of fluid — water, tea, milk, and water in foods.

  • Base: weight in kg × 32 ml
  • + 350 ml for moderate activity, + 700 ml for high (clinical heuristic, not NIN-DGI)
  • + 400 ml for hot/humid, + 800 ml for very hot (clinical heuristic, not NIN-DGI)

Roughly 20 % of daily fluid usually comes from food (fruit, vegetables, dal, curries). The rest should come from drinks — ideally mostly plain water.

Sources

  • ICMR-NIN. Dietary Guidelines for Indians 2024, Guideline 14 (Drink adequate quantity of water), p.89–92.
  • EFSA Panel on Dietetic Products, Nutrition, and Allergies. Scientific Opinion on Dietary Reference Values for water. EFSA Journal 2010;8(3):1459.
  • Institute of Medicine (US). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. 2005.