๐ง Water Intake Calculator
* This is a general guideline, not medical advice. Consult a doctor if you have a medical condition.
Enter your body weight and daily activity level to estimate your recommended daily water intake. Based on roughly 33 ml per kg of body weight, plus extra for exercise-related sweat loss. Useful for staying hydrated or planning for hot weather.
How to use
- Enter your body weight in kg.
- Choose your typical activity level (sedentary, light exercise, moderate exercise, or intense exercise).
- Your recommended daily water intake is shown automatically.
How the calculation works
This tool takes 33 ml per kg of body weight as a baseline daily intake and adds an allowance for activity, giving a guide to how much to drink. The formula is weight (kg) ร 33 ml + activity allowance. The allowance is 0 ml for little activity, 350 ml for light exercise, 650 ml for moderate exercise and 1,000 ml for intense exercise โ the more you sweat, the more water you lose. We also get water from food, and the body produces some water as it breaks down nutrients, so treat this figure as a guide to what to drink. Hot weather, bathing and fever all raise your needs further.
Worked example
60 kg with moderate exercise Baseline: 60 ร 33 = 1,980 ml Activity allowance: 650 ml Total: about 2,630 ml Drinking a glass (about 200 ml) roughly ten times through the day is said to be absorbed better than drinking a lot at once.
Things to be aware of
- This is a general guide; needs change with temperature, humidity and health.
- If you have kidney or heart disease, or have been told to restrict fluids, follow your doctor's instructions.
- Drinking regularly before you feel thirsty helps prevent heatstroke.
- After heavy sweating, replace salt (sodium) as well as water.
FAQ
What's this calculation based on?
It's based on the common guideline of about 33 ml per kg of body weight, plus an estimated addition for sweat loss based on activity level. Individual needs vary, so treat this as a rough guide.
Does this include water from food?
No โ this shows a guideline for water from drinks only. Since food also provides some hydration, the amount you actually need to drink may be slightly lower.
Is this applicable if I have kidney or heart conditions?
No โ water intake for people with existing medical conditions should follow a doctor's guidance. This tool is a general guideline for healthy individuals.