How Much Water Should You Drink Per Day?
Adequate hydration is essential for virtually every bodily function — regulating temperature, transporting nutrients, flushing waste, and lubricating joints. The widely cited '8 glasses a day' rule is a rough approximation. A more accurate approach scales intake to body weight and activity level, as larger and more active people need significantly more water.
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Formula
Daily Water Intake
Calculate your recommended daily water intake based on weight and activity.
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Worked Example
Given:
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FAQs
Does coffee and tea count toward daily water intake?
Yes — caffeinated drinks do contribute to hydration despite being mild diuretics. The net effect of tea and coffee is still hydrating for most people at normal consumption levels. Alcohol, however, causes net fluid loss and should not be counted.
How do I know if I am drinking enough water?
The simplest indicator is urine colour. Pale yellow indicates good hydration. Dark yellow or amber suggests you need more water. Clear urine may indicate overhydration. Thirst is a reliable signal in healthy adults, though older adults may have a diminished thirst response.
Do I need more water in hot weather or during exercise?
Yes significantly. Sweating during exercise or in heat can increase fluid losses to 1–2 litres per hour. Sports guidelines recommend drinking 500 mL of water 2 hours before exercise, sipping regularly during exercise, and rehydrating after based on weight lost during the session.