What this calculator measures
Adequate hydration supports exercise performance, recovery, and cognitive function. Mild dehydration of even 1–2% of body weight can measurably reduce endurance and strength. This calculator estimates a practical starting range — individual needs vary significantly with climate, sweat rate, and diet.
How this calculator works
The baseline range uses 30–35 ml per kilogram of body weight per day — consistent with general population hydration recommendations from ACSM's exercise and fluid replacement position stand (2007). Training adjustments account for average sweat losses, with additional guidance for hot or humid conditions.
How to use your result
Use urine colour and thirst as real-time indicators alongside this estimate. Pale yellow urine typically indicates adequate hydration. For endurance sessions over 60 minutes, consider sodium replacement alongside extra fluid to prevent hyponatraemia. Caffeinated drinks, fruits, and vegetables all contribute to total daily fluid intake.
Important limitation
Calculator results are estimates. Pregnancy, eating disorders, medical conditions, injuries, or concerning symptoms require qualified professional guidance.