Free online water intake calculator: calculate how much water you should drink daily based on your weight and activity level. Get recommended daily water intake in milliliters, liters, cups, and fluid ounces. Follow Institute of Medicine guidelines for proper hydration. Perfect for health enthusiasts, athletes, fitness trainers, and anyone looking to optimize their hydration habits. Simply enter your weight and select your activity level to get personalized water intake recommendations. Mac OS 9 retro style. No signup required.
Enter your current weight. You can switch between Metric (kg) and Imperial (lb) units using the toggle button at the top.
Choose your typical activity level from Sedentary to Extremely Active. More activity means your body needs more water to stay hydrated.
Click Calculate to see your personalized daily water intake recommendation displayed in multiple units: milliliters, liters, cups, and fluid ounces.
Q: Is 8 glasses of water per day accurate for everyone?
A: No, individual water needs vary. This calculator personalizes the recommendation based on your weight and activity level for a more accurate estimate.
Q: Does caffeinated coffee or tea count toward water intake?
A: While caffeine has a mild diuretic effect, moderate consumption of coffee and tea can still contribute to your daily fluid intake. However, plain water is the most effective for hydration.
Q: How does exercise affect my water needs?
A: Exercise increases water loss through sweat. For every 30 minutes of moderate exercise, add about 12 oz (355 mL) of water to your daily intake. More intense or longer sessions need more.