Find your personalized daily hydration goal based on weight and activity
Tracking health metrics shouldn't require doctor visits for every quick estimate. Water Intake Calculator lets you find your personalized daily hydration goal based on weight and activity instantly with science-backed formulas. All calculations run in your browser, and no personal health data is stored or transmitted anywhere.
General guidelines suggest 8 cups (64 oz / 1.9L) per day, but individual needs vary significantly based on weight, activity, climate, and health status. The formula used here — 0.5 oz per pound of body weight — is a commonly recommended starting point. Adjust based on thirst and urine color (pale yellow = well hydrated).
Yes, beverages like coffee, tea, juice, and milk all contribute to your daily fluid intake. While caffeinated drinks have a mild diuretic effect, moderate coffee and tea consumption (up to 3–4 cups/day) still results in net positive hydration. Plain water is best, but don't exclude other beverages from your count.
Common signs include dark urine (amber to dark yellow), infrequent urination (less than 4 times/day), dry mouth, fatigue, headache, and dizziness. Even mild dehydration (1–2% of body weight in fluids) can impair physical and cognitive performance. Don't wait until you're thirsty — thirst is already a mild dehydration signal.