Water Intake Calculator

Thirst is not a reliable early indicator of hydration status — it kicks in after you're already mildly dehydrated (1–2% body weight loss). For active individuals, athletes, and the elderly, thirst lags significantly behind actual needs. Schedule water intake proactively rather than waiting for thirst signals.

Yes, with a caveat. Despite the common myth, caffeinated beverages are NOT significantly dehydrating at typical consumption levels. The mild diuretic effect of caffeine is more than offset by the water content of the drink. One cup of coffee counts as roughly 0.5–0.75 cups of water for hydration purposes. However, alcohol is actively dehydrating and should not count.

Mild (1–2% body weight): increased thirst, darker urine (aim for pale yellow), dry mouth, slight headache. Moderate (3–5%): decreased urine output, significant headache, fatigue, reduced concentration, muscle cramps. Severe (6%+): very dark or no urine, dizziness, rapid heartbeat, confusion — seek medical attention.