Lunia · Free tools
Water Intake Calculator
Explore a rough weight-based fluid range and put exercise needs in context.
Your details
Runs entirely in your browser. Nothing you type is sent anywhere or saved.
Your result
Ready to calculate
Enter your details, then calculate to see your result here.
How this calculator works
A rough comparison is 30 to 35 mL per kg per day, a range used in adult nutrition-support guidance. That clinical context does not make it a universal target for healthy athletes, and total fluid can come from several sources. Exercise duration is displayed as context, without adding a fixed amount that ignores sweat loss, temperature and medical needs.
A worked example
Body weight: 70 · Weight unit: Kilograms · Exercise duration for context (min): 30
- Rough daily fluid starting range
- 2.1 to 2.45 L
- Exercise duration entered
- 30 min
- Exercise adjustment
- Use sweat loss, thirst and conditions, not a fixed extra allowance.
These are illustrative inputs, not personal recommendations.
Common questions
Should I force myself to drink the upper number?
No. This range is only a starting comparison. Excessive water intake can be harmful, and a personal fluid plan should account for actual conditions.
How should I use the result?
Fluid requirements vary widely with food moisture, weather, sweat rate and health. Pregnancy and breastfeeding alter needs. Follow individual advice if you have a fluid restriction, kidney disease or heart failure.
Sources & method references
Formula-based results are estimates, not individual medical advice.