Water Intake Calculator CA
Estimate how much water to drink each day based on your body weight and how much you exercise.
General estimate using standard formulas — not medical or dietary advice. For personalised guidance, speak to a qualified professional.
How it works
Enter your body weight and how many minutes you exercise each day. The calculator estimates daily water using about 35 ml per kilogram of body weight, plus extra to replace fluid lost during exercise.
Frequently asked questions
How much water should I drink a day?
A common guide is about 30–35 ml per kg of body weight — roughly 2–2.7 litres for women and 2.5–3.7 litres for men, including water from food and other drinks.
Does tea, coffee or food count towards hydration?
Yes. Most drinks and many foods contribute to your fluid intake; a good portion of daily water comes from food.
Do I really need 8 glasses of water?
“8 glasses” is a rough rule of about 2 litres. Actual needs vary with body size, activity and climate, so use it as a guide rather than a fixed target.
How much extra water do I need when exercising?
Roughly an extra 0.5–1 litre for each hour of exercise, and more in hot conditions to replace what you lose through sweat.
Can you drink too much water?
Very rarely, drinking far too much in a short time can dilute blood sodium (hyponatraemia). For most people, spreading normal amounts through the day is safe.
How do I know if I am well hydrated?
Pale-yellow urine and not feeling thirsty are reliable everyday signs of good hydration.
Water Intake Calculator
How much water you need depends on your body size, how active you are and your climate. This calculator gives a sensible daily target based on those factors.
How much water per day?
A common rule of thumb is around 30–35 ml of fluid per kilogram of body weight. General guidelines suggest roughly 2–2.7 litres a day for women and 2.5–3.7 litres for men, including the water you get from food and other drinks.
When you need more
- Exercise: add roughly 0.5–1 litre for each hour of activity.
- Hot weather increases losses through sweat.
- Pregnancy, breastfeeding or illness raise your needs.
Signs you are well hydrated
Pale-yellow urine and rarely feeling thirsty are good signs. Dark urine or persistent thirst suggests you should drink more.
Needs vary, and some medical conditions (such as kidney or heart conditions) require fluid limits — follow your doctor’s advice in that case.
Results are estimates for general guidance in Canada and may not reflect the latest local rates, fees or rules. Check official sources before making decisions.