Add fluid needs from exercise.
Hydration needs for Hydration by Activity start from body weight and add allowances for prolonged activity and hot conditions, where sweat losses climb. Fluid needs track body size and sweat loss, so a fixed daily target fits nobody precisely.
Hydration by Activity
Water = 33 mL x weight + activity allowance + heat allowance
These figures are population-average estimates for general planning only and are not medical or dietetic advice. Individual energy and nutrient needs vary widely with body composition, activity, medication and health status. Consult a qualified health professional or registered dietitian before making significant changes to what you eat, and especially if you are pregnant or breastfeeding, are under 18, or have a medical condition or a history of disordered eating.
Water = 33 mL x weight + activity allowance + heat allowance Hydration needs for Hydration by Activity start from body weight and add allowances for prolonged activity and hot conditions, where sweat losses climb.
Fluid needs track body size and sweat loss, so a fixed daily target fits nobody precisely.
This calculator takes 3 inputs: Body weight, Activity, Temperature. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.