Water Intake Calculator
Enter your body weight and daily exercise minutes to estimate how much water you should drink per day.
Last updated: September 25, 2026
Frequently asked questions
How much water should I drink based on my weight?
A common guideline is half your body weight in pounds, converted to ounces - a 180 lb person would target about 90 oz per day before accounting for exercise.
Does exercise increase how much water I need?
Yes - sweat losses during exercise increase your fluid needs. This calculator adds roughly 12 oz for every 30 minutes of activity as a general estimate.
Is a 'weight and water calculator' the same as this tool?
Yes - this calculator estimates your daily water intake target based on your body weight (plus activity level), which is exactly what that phrase describes.
Does this account for water from food, not just drinks?
No - this estimates fluid intake from drinking specifically; roughly 20% of daily water intake typically comes from food, so your actual total hydration needs are somewhat lower than the drinking-only figure this calculator returns.
Do coffee and tea count toward daily water intake?
Yes, in moderation - while caffeine has a mild diuretic effect, research shows moderate coffee and tea consumption still contributes net hydration rather than causing dehydration. Water remains the most reliable source, but you don't need to exclude other beverages entirely from your daily total.