There is no single right amount of water for everyone. Needs depend on body size, activity, climate, diet and health. This calculator gives a rough daily estimate from your weight, activity level and climate, shows it in liters, US fluid ounces and 8-ounce cups, and explains the difference between total water and the water you drink.
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Estimates are educational. They do not diagnose any condition and do not establish eligibility for any medication. A licensed provider decides what is appropriate for you. Explore treatments if you want to learn about provider-guided programs.
An approximate daily total water intake, meaning all the water your body takes in from drinks and food. About 80 percent of total water typically comes from beverages (including coffee, tea and milk) and about 20 percent from food, so the calculator also shows the beverage share.
The method is a simple, clearly labeled estimate, not a clinical formula:
Total water (L) = 0.035 × weight (kg) + activity addition + climate addition
Results are shown in liters, US fluid ounces (1 L = 33.814 fl oz) and 8 fl oz cups. Pounds are converted to kilograms first.
The National Academies (2005) set an adequate intake for total water of about 3.7 L per day for men and 2.7 L per day for women, derived from median intakes in healthy populations. They note that most healthy people meet their needs by letting thirst guide them. The CDC also points out that recommended intake varies with age, sex, activity, pregnancy and breastfeeding.
Eight 8-ounce glasses is about 1.9 L, a reasonable amount of drinking water for many people, but it is not a research-based rule. The National Academies adequate intake for total water is about 3.7 L for men and 2.7 L for women, and that total includes food and all beverages.
Yes. Caffeinated drinks contribute to total water intake. The mild diuretic effect of caffeine does not cancel out the fluid in the drink for regular consumers.
Because official adequate intake values are for total water from all sources, while most people think about what they drink. Roughly 80 percent of total water comes from beverages and 20 percent from food, so the calculator shows both.
Many people on weight programs eat less food, which means less water from food, and some report reduced thirst. Keeping up fluid intake supports digestion and general comfort. A licensed provider can advise if you have questions specific to your plan.
Follow the limit your care team gave you. This calculator is not appropriate for anyone with a fluid restriction, which is common with heart failure, kidney disease and some other conditions.
Pale yellow urine, infrequent thirst and steady energy are practical signs for most healthy adults. Dark urine, headaches and dizziness can signal you need more, especially in heat.
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