- Enter your weight. Body weight is the primary driver of fluid requirements. A common baseline is half your body weight in ounces: a 160-lb person needs about 80 oz (10 cups) per day before adjustments for activity and climate.
- Select your activity level. Exercise increases sweat losses significantly. Light activity adds about 12 oz to the base. Heavy exercise (1+ hours at intensity) can add 24-32 oz or more depending on sweat rate and duration.
- Select your climate. Hot or humid environments increase fluid loss through sweat. Air conditioning and cold climates reduce the adjustment. Living or working in dry air (high altitude, heated buildings in winter) also increases fluid needs.
- Read results in all units. The recommendation is shown in fluid ounces, glasses (8 oz), cups, liters, and milliliters to match whatever measurement you prefer for tracking.
Water Intake Calculator
Find out how much water you should drink per day based on weight, activity, and climate.
lbs
Daily Water Intake
14
glasses (8 oz each)
| Total Ounces | 112 oz |
| Total Liters | 3.30 L |
| Total Cups | 13.9 cups |
| Total mL | 3297 mL |
Breakdown
Base (weight/2): 88 oz
Activity add-on: +16 oz
Climate add-on: +8 oz
How to Calculate Your Daily Water Intake
Frequently Asked Questions
The National Academies of Sciences recommends 3.7 liters (125 oz) per day total fluid intake for men and 2.7 liters (91 oz) for women, including all beverages and food. About 20% comes from food, so daily drinking targets are approximately 3.0 liters (100 oz) for men and 2.2 liters (73 oz) for women. These are baselines for sedentary adults in temperate climates. Exercise, heat, pregnancy, and breastfeeding all increase needs.
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