Daily Water Intake Calculator
Get a personalised daily water intake target based on your body weight, activity level, and climate.
Signs of good hydration
- Urine is pale yellow throughout the day
- You rarely feel thirsty
- Skin has good elasticity (pinch test bounces back quickly)
- Energy levels stay stable between meals
Frequently asked questions
How much water should I drink per day?
The classic '8 glasses (2 litres) per day' guideline is a reasonable starting point, but actual needs vary widely. This calculator uses a weight-based formula (roughly 30-35 ml per kg, or 0.5 oz per pound) and adjusts for activity level and climate — giving a personalised target.
Does coffee and tea count?
Yes. Modern research shows that caffeinated drinks are net hydrating despite mild diuretic effects. Coffee, tea, sparkling water, and even the water content of fruits and vegetables all count toward your daily total.
Can I drink too much water?
Yes, but it's rare in normal conditions. Drinking huge amounts of water very quickly (typically 3-4+ litres in a few hours) can cause hyponatremia — dangerously low blood sodium. Spread intake throughout the day and listen to your thirst signals.
How can I tell if I'm well-hydrated?
Urine colour is a reliable indicator. Pale yellow (like lemonade) is well-hydrated. Dark yellow suggests you need more water. Very clear urine can indicate over-hydration. Thirst is also a reasonable guide for most healthy adults.
This calculator provides general estimates for healthy adults. People with kidney disease, heart failure, or certain medications may need different amounts. Consult a doctor for personalised advice.