Health & Fitness
Calculate your recommended daily water intake based on weight, activity, and climate
Last reviewed: How we build & verify
Liters / Day
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Glasses / Day
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Ounces / Day
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Hydration Tips
- Drink water consistently throughout the day, not all at once
- Increase intake during exercise, illness, or hot weather
- Foods like fruits and vegetables contribute to hydration
- Urine color is a good indicator — aim for pale yellow
How it works
Estimates daily fluid needs from body weight, activity, and climate. Total intake includes water from food, which typically supplies 20-30% of the requirement.
Formula
Baseline ≈ 35 ml per kg of body weight
Variables
35 ml/kgtypical adult baseline+500-1000 mladded per hour of vigorous exercise
Worked example
Inputs: 75 kg adult, 1 hour of training
- Baseline: 75 × 35 = 2,625 ml
- Exercise: +700 ml
Result: ≈ 3.3 litres/day
Notes
- Pale straw-coloured urine is a more reliable indicator than hitting any numeric target.
- Hyponatraemia from drinking far in excess of losses is rare but dangerous, and endurance athletes should replace sodium too.
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Frequently Asked Questions
A common guideline is 30-35 mL per kg of body weight (about 0.5-0.7 oz per lb). A 70 kg adult needs roughly 2.1-2.5 L per day from all sources; food contributes about 20% of that.
Yes. Research shows that moderate caffeine intake does not cause net dehydration. Coffee and tea contribute to daily fluid needs, though plain water is still the best source.
Exercise, hot climates, high altitude, pregnancy, breastfeeding, fever, and high-protein or high-fibre diets all increase water requirements.