Fit Nutrition library
Water Intake Calculator
Estimate a practical daily fluid starting point.
How it’s calculated
A FitNutrition weight-based estimate. Baseline is ~30–40 mL of fluid per kg of body weight per day (e.g. 70 kg → about 2.1–2.8 L). Increase intake above this only when you have extra losses — training, hot weather, illness, or pregnancy/breastfeeding. Food and other drinks count toward the total. This is a general estimate, not a medical requirement; people with heart, kidney, or fluid-restriction conditions should follow their clinician's advice.