Daily Water Intake Calculator
This tool estimates your daily water needs from your weight and activity level (about 30–35 ml per kilogram of body weight, more with exercise or hot weather). Enter your weight and choose your activity level. The result is a guide for healthy adults; kidney or heart patients should set fluid targets with their doctor.
Activity / weather
Medical disclaimer: This tool is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
Frequently asked questions
How many liters of water do I need daily?
A practical rule for healthy adults is 30–35 ml per kg of body weight: a 70 kg person needs about 2.1–2.5 liters daily, more with exercise, heat, pregnancy, or breastfeeding.
Do tea and coffee count toward fluids?
Yes, they count toward daily fluids, but water remains the best choice. Excess caffeine can increase urination, so do not rely on caffeinated drinks as your main source.
Is drinking lots of water always good?
No; extreme overhydration can cause low blood sodium, especially in kidney or heart patients or those on diuretics — such patients should set fluid limits with their doctor.