Water Intake Calculator
Calculate how much water you should drink daily based on your weight, activity level, and climate. Stay properly hydrated for better health.
Enter your information to calculate your daily water needs.
How It Works
This calculator uses your body weight as a baseline, then adjusts for activity level and climate. The general guideline is 0.5-1 ounce per pound of body weight daily, with active people and those in hot climates needing more.
Water needs vary significantly by individual. Factors beyond weight include muscle mass, age, health conditions, medications, and diet. These recommendations are general guidelines—listen to your body's thirst signals.
Signs of proper hydration include clear to light yellow urine, rarely feeling thirsty, and having consistent energy levels. Dark urine, dry mouth, and fatigue can indicate dehydration.
Frequently Asked Questions
Is the "8 glasses a day" rule accurate?
The 8×8 rule (eight 8-ounce glasses = 64 oz) is a reasonable average but not based on strong science. Individual needs vary widely—a 200-lb active person needs more than a 120-lb sedentary person. Use body weight as a better guide.
Does coffee and tea count toward water intake?
Yes, caffeinated beverages do contribute to hydration despite mild diuretic effects. The fluid in coffee and tea offsets any increased urination. However, water and unsweetened beverages are best for overall health.
Can I drink too much water?
Yes, but it's rare. Overhydration (hyponatremia) occurs when you drink so much that sodium levels become dangerously diluted. It's most common in endurance athletes. For most people, the kidneys handle excess water efficiently.
How much extra water do I need when exercising?
Add 12-16 oz for every 30 minutes of exercise. For intense or prolonged exercise (over 60 minutes), consider a sports drink to replace electrolytes. Weigh yourself before and after exercise—drink 16-24 oz for every pound lost.
What are signs of dehydration?
Early signs: thirst, dark yellow urine, dry mouth, fatigue. Moderate dehydration: headache, dizziness, decreased urination. Severe: rapid heartbeat, confusion, fainting. Chronic mild dehydration affects energy, cognition, and skin health.