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Free Water Intake Calculator

Find how much water to drink each day based on your weight, exercise and climate β€” in litres, cups, fluid ounces and glasses, with the drinks-vs-food split. Metric or imperial, private and free.

Works offline once loaded

Estimate your daily water target from your weight, activity and climate. Everything is calculated privately in your browser.

Units
kg
Climate
Adjustments
Recommended daily water
πŸ’§ 2.66 L
per day Β· 90 fl oz
11
glasses (250 mL)
11
cups (240 mL)
Your bottle or cup
mL

β‰ˆ 5.3 refills of your 500 mL container per day

β‰ˆ 2.13 L from drinks β€” you get the rest from food.

⚠️ This is general guidance for healthy adults, not medical advice. Your needs change with health conditions, medication, pregnancy, breastfeeding and individual physiology. Don't force large amounts at once β€” and if you have a heart or kidney condition, ask your doctor about fluid limits.

πŸ”’ Your weight and activity never leave your device β€” everything is calculated in your browser.

Common uses

  • How Much Water Should I Drink a Day?Find your personalised daily water target from your weight, activity and climate.
  • Water Intake by Body WeightCalculate daily water from your body weight in kilograms or pounds.
  • Daily Water Intake CalculatorGet your total daily fluid target in litres, cups, ounces and glasses.
  • Water Intake for Weight LossSee your hydration target and why water supports a weight-loss routine.
  • Water Intake for ExerciseAdjust your daily water goal for how much you train.
  • How Many Ounces of Water Per DayConvert your daily water target into fluid ounces and cups.

How It Works

Estimates how much water to drink each day from your body weight, daily exercise and climate. The baseline is about 33 mL per kilogram (the midpoint of the common 30–35 mL/kg guidance), plus roughly 350 mL for every 30 minutes of exercise, with an uplift for warm or hot conditions. Results are shown in litres, cups, fluid ounces and glasses. Everything is computed in your browser.

  1. 1
    Enter your weight
    Heavier bodies need more water. Switch between metric (kg) and imperial (lb) at any time.
  2. 2
    Add daily exercise and climate
    More activity and hotter weather increase how much you lose through sweat, so the target goes up.
  3. 3
    Read your target
    You get a daily total in litres, cups, fluid ounces and glasses, plus the share that comes from drinks (about 80%) versus food (about 20%).
  4. 4
    Spread it across the day
    Sip regularly rather than all at once, and drink more around exercise or heat. Thirst and pale-yellow urine are good everyday guides.

Your weight and activity never leave your device β€” every number is computed locally in your browser.

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Frequently Asked Questions