Enter your weight, activity level and climate to get an estimated daily water target in liters, ounces and cups. Instant results, no signup. A general estimate for healthy adults, not a medical prescription.
Reference values for adults are given as total water: about 3.7 liters a day for men and 2.7 liters for women in the US (National Academies), and 2.5 / 2.0 liters in Europe (EFSA). Roughly 20% of that typically comes from food. Our water intake calculator, sometimes called a hydration calculator, turns your body weight, activity and climate into a personal daily estimate. See the methodology and sources.
Body weight is the starting point of this calculator. SnapWaterCalc uses 33 ml per kilogram (about 0.5 fl oz per pound) as its own baseline scaling rule before applying activity, climate and biological sex. It is not a general recommendation published by EFSA or the U.S. National Academies; those organizations publish population-level reference intakes rather than a single ml-per-kilogram target. See the daily water intake chart by weight, or a specific weight: 60 kg, 70 kg, 80 kg, 100 kg, 150 lbs, 180 lbs, 200 lbs.