Water Intake Calculator

📋 What Your Result Means

For educational purposes only — not medical advice.

Your daily water target is personalized to your body weight, activity level, and environmental conditions. For active individuals, this will typically exceed the generic "8 glasses a day" advice, which has no strong scientific basis (Valtin 2002, DOI: 10.1152/ajpregu.00365.2002).

All fluids count. Coffee, tea, milk, and water-rich foods (fruits, vegetables, soups) all contribute to your daily total. Contrary to popular belief, moderate caffeine intake (up to 400 mg/day) does not cause net dehydration in habitual consumers (Killer et al. 2014, DOI: 10.1371/journal.pone.0084154).

Urine color is your best real-time indicator. Aim for pale straw color. Dark yellow means you are behind; completely clear may indicate overhydration. During exercise, weigh yourself before and after — each kg lost represents roughly 1 liter of fluid to replace.

Electrolytes matter as much as volume. During prolonged exercise (over 60 minutes) or heavy sweating, plain water alone is insufficient. Sodium, potassium, and magnesium losses must be replaced to maintain performance and prevent hyponatremia (Sawka et al. 2007, DOI: 10.1249/mss.0b013e31802ca597).

Want to learn more? Read our in-depth article: How Much Water Should You Drink Per Day? →