Hydration Calculator · 2026

Daily Water Intake Calculator How much should you drink today?

Get your personal daily water target based on weight, activity, climate, and life stage. Uses peer-reviewed IOM hydration guidelines.

~30s
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IOM
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How many minutes of moderate-intense exercise you do per day
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Fill in your details to see your daily target.

How It Works

The math behind your number.

Based on IOM hydration guidelines + adjustments for activity, climate, and life stage.

The Formula

  • Base: 35 ml × your weight (kg) — IOM recommendation for healthy adults
  • Activity bonus: +12 ml × minutes of exercise (replaces sweat losses)
  • Hot climate: +500 ml/day adjustment for high heat or humidity
  • Pregnancy: +300 ml/day per recommended guidelines
  • Breastfeeding: +700 ml/day for milk production

Important Notes

  • This is your total fluid target — including water from food (~20%)
  • Coffee, tea, and milk all count toward fluid intake
  • Sugary drinks "count" but offset health benefits
  • Listen to your body — thirst and urine color are reliable signals
  • People with heart/kidney conditions should follow doctor's specific advice
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All tools are free, no signup, no email. Built using peer-reviewed formulas where applicable.