Quick answer: the U.S. National Academies set total water at about 3.7 L (125 oz) a day for men and 2.7 L (91 oz) for women, including water from food. From drinks, that is roughly 11–15 cups for men and 8–11 cups for women, plus more when you exercise or it is hot.
Daily Water Intake Chart
| Weight | Women | Men |
|---|---|---|
| 110 lb | 64 oz | 78 oz |
| 130 lb | 69 oz | 83 oz |
| 150 lb | 74 oz | 88 oz |
| 170 lb | 80 oz | 93 oz |
| 190 lb | 85 oz | 98 oz |
| 210 lb | 90 oz | 103 oz |
| 230 lb | 95 oz | 108 oz |
| 250 lb | 100 oz | 113 oz |
How the Water Calculator Works
It averages two common approaches: the National Academies’ Adequate Intake (about 80% of which normally comes from drinks) and about 33 ml per kg of body weight. It then adds about 0.6 L for each hour of exercise and 0.5 L for hot weather. These are averages; your thirst and urine color are good day-to-day guides.
Signs You Need More Water
Dark yellow urine, thirst, headache, fatigue and dizziness can mean mild dehydration. Older adults feel thirst less, so they benefit from drinking at regular times. Drinking far more than you need in a short time can be dangerous (hyponatremia), especially during long endurance events, so drink to thirst rather than forcing large volumes.
Tips to Drink More Water
Keep a bottle in sight, drink a glass with every meal, and add water-rich foods such as fruit, vegetables and soup. Tea, coffee and milk count toward your total. When training, weigh yourself before and after: each pound lost is about 16–24 oz to replace. Pair good hydration with enough fiber for healthy digestion.
Water Intake FAQ
How much water should I drink a day?
Most women need about 8–11 cups of fluid from drinks and most men 11–15 cups, more with exercise or heat. The calculator gives a personal target from your weight.
Is 8 glasses of water a day right?
It is a reasonable minimum for many people, but needs vary with size, activity and climate. Food and other drinks also count.
Does coffee count toward water intake?
Yes. Moderate coffee and tea are hydrating overall despite their mild diuretic effect.
How much water should I drink to lose weight?
Drinking water before meals may help you eat less, but there is no special amount for weight loss. Meet your normal needs and replace sugary drinks with water.
Can you drink too much water?
Yes. Drinking several liters very quickly, or far more than you sweat during endurance exercise, can dilute blood sodium (hyponatremia), which can be dangerous.
Sources
- National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. 2005.
- European Food Safety Authority. Scientific Opinion on Dietary Reference Values for water. EFSA Journal. 2010;8(3):1459.
- American College of Sports Medicine. Exercise and fluid replacement. Medicine & Science in Sports & Exercise. 2007;39(2):377–390.
For general information for healthy adults. It is not medical advice; talk to a doctor before starting a new exercise or diet plan if you have a health condition.