Water Intake Calculator
Estimate daily fluid needs in litres and cups from body weight and activity (33 ml/kg method with activity adjustment)
Your hydration estimate
Enter weight and activity, then tap Calculate for daily litres, millilitres, and cup equivalents.
Your hydration estimate
Base: 33 ml per kg body weight, adjusted for activity. Pregnancy, breastfeeding, kidney disease, and heart conditions may require different intake — ask your clinician.
About this method
Formula
Daily ml ≈ weight (kg) × 33 × activity factor. Converted to litres and standard 240 ml cups.
When needs increase
Hot weather, fever, diarrhoea, vigorous sport, pregnancy, and high altitude raise fluid requirements.
Limitations
Does not replace personalised advice for heart failure, dialysis, or fluid-restricted diets.
Frequently asked questions
How much water should I drink daily?
Needs vary by weight, climate, activity, pregnancy, and health conditions. This tool uses ~33 ml per kg body weight with an activity multiplier as a general estimate.
Does this include all fluids?
Total fluid intake includes water, other drinks, and moisture in food. Thirst, urine colour, and clinician advice remain important guides.
Who should not follow a high-fluid plan?
Heart failure, kidney disease, dialysis, and some medications require fluid limits. Always follow personalised medical instructions.