Water Intake Reference Calculator

The EFSA values used here are adequate-intake references for total water: 2.0 litres per day for adult women and 2.5 litres for adult men. Total water includes water in foods as well as drinking water and other beverages. These values were set for moderate environmental temperature and moderate physical activity; they are not a rule that each person must drink that quantity of plain water. Food moisture can contribute meaningfully, and the share varies with eating patterns and the foods chosen.

Because the tool cannot inspect what you eat, the food contribution is an explicit assumption that you can vary from zero to 50 percent. The displayed beverage amount is the remainder of the chosen total reference after that assumed share. It includes all beverages, not extra plain water to add on top. The cup count uses a 250 mL cup for a familiar comparison. It is only an arithmetic translation, not a hydration prescription, and the assumed food fraction is not measured or personalized.

Fluid needs vary with heat, activity, illness, diet, body size, pregnancy, breastfeeding, medications and health conditions. Thirst and clinician guidance may be more relevant than a general reference in a particular situation. People with kidney or heart conditions, prescribed fluid limits, or pregnancy-related questions should seek individualized advice before changing intake. A generic calculator cannot account for fluid balance or determine whether a person is dehydrated or overhydrated.

Do not use the beverage number to force a large amount of fluid or to ignore symptoms. Drinking excessive water can be harmful, and needs change over a day. This page does not recommend a weight-based millilitres-per-kilogram rule; the reference is intentionally based on EFSA total-water values and shows its assumptions. If you are unsure whether your usual intake is appropriate, discuss the question with a qualified professional who knows your circumstances. A calculated reference is for understanding the distinction between total water and beverages, not a treatment plan.