Get a personalized daily water target based on your body weight, activity level, and environment.
Suggested drinking schedule
About 20% of daily water comes from food. This calculator shows total fluid intake including beverages.
The baseline formula uses 0.5–1.0 ounces of water per pound of body weight, adjusted for activity and climate. Sedentary individuals in cool climates need less; active people in hot environments need significantly more.
The U.S. National Academies of Sciences recommends about 125 oz/day (3.7L) for men and 91 oz/day (2.7L) for women as a general guideline, but individual needs vary widely based on body size, exercise, and environment.
Mild dehydration (1–3% body weight loss) can impair mood, concentration, and physical performance before you feel obviously thirsty. Common signs include dark yellow urine, headache, fatigue, dry mouth, and reduced urine frequency. By the time you feel thirsty, you're already mildly dehydrated.
The simplest hydration check: look at your urine color. Pale straw yellow means well-hydrated. Dark yellow or amber means drink more water.
Yes. While caffeine is a mild diuretic, the net hydration effect of coffee and tea is still positive. A cup of coffee provides almost as much hydration as a cup of water. However, water and herbal tea remain the best primary sources.
Yes, though it's rare. Hyponatremia (water intoxication) occurs when you drink so much water that blood sodium levels drop dangerously. It's mainly a risk during extreme endurance events. For most people, your kidneys can handle up to 1 liter per hour without issues.
Staying hydrated can support weight loss in several ways: it reduces appetite (thirst is often confused with hunger), slightly increases metabolic rate, and improves exercise performance. Drinking a glass of water before meals has been shown to reduce calorie intake.