This tool starts from about 35 ml per kilogram of body weight, then adds fluid for activity (up to 1 liter for very active days) and hot climates. That covers a typical day — training days, illness, pregnancy and some medications shift needs.

  • Keep water visible — a bottle on the desk beats willpower.
  • Drink a glass with each meal and around workouts.
  • Fruit, vegetables, soups, tea and coffee all count.

Hydration needs vary with activity, environment, diet and medical circumstances — this is an educational estimate, not a prescription. Read more on Hydration and Nutrition.