Daily water intake calculator

How the water intake estimate works

The calculator starts from a widely used guideline of 33 ml per kilogram of body weight (about 0.5 fl oz per pound) per day. That covers all the water your body needs, including water in food such as fruit, vegetables and soup, which supplies roughly 20%.

\[ \begin{gathered} \text{Total need (ml)} = \text{weight (kg)} \times 33 + \text{pregnancy} \ 300 \, \text{or breastfeeding} \ 700 \\ \text{To drink} = 80\% \, \text{of the base need} + 350 \, \text{ml per} \ 30 \, \text{min of exercise} + 500 \, \text{ml in very hot weather} \end{gathered} \]

For reference, 1 US fluid ounce is 29.57 ml and a cup is 8 fl oz.

Water needs by body weight

Signs you are well hydrated

Pale yellow urine and rarely feeling thirsty are good signs. Dark urine, headaches, a dry mouth or fatigue can mean you need more. Sipping through the day works better than drinking a lot at once. Coffee, tea and soup count toward the total.

Water intake calculator: examples by body weight

Here are simple calculations. Multiply your weight in kilograms by 33 ml. Then take 80% of the total for the part you drink. For example, at 60 kg (132 lb), you get 1.98 liters, or 1.6 liters to drink, about 54 oz. At 90 kg (198 lb), the total is 2.97 liters, with 2.4 liters from drinks.

So your water need rises with weight. In contrast, a very active person adds another 16 to 32 oz. How much water to drink depends on your lifestyle, not only your weight.

Water intake calculator: tips to reach your goal

Drinking enough becomes easy with a few habits. First, have a large glass when you wake up. Then keep a bottle on your desk. Next, drink before every meal. Finally, add lemon or mint if plain water tastes dull.

• Soup, fruit and vegetables count toward your intake.
• Tea and coffee count too, in moderation.
• Alcohol dehydrates, so do not count it.

Also, do not drink it all at once: spread it through the day.

Water intake calculator: health notes and related tools

Watch your urine color: pale yellow is ideal. However, some cases need medical advice, such as pregnancy, kidney stones or heart failure. Therefore, this estimate is only a guide.

To track your fitness, use the BMI calculator and the calorie calculator. To compare volumes, open the unit converter. Finally, the online timer can remind you to drink every hour.

Water intake calculator: special cases

Some people have different needs. During pregnancy, add about 10 oz a day, and 24 oz while breastfeeding. For children, the need runs from about 34 to 54 oz depending on age. Older adults feel less thirst, so they must remember to drink regularly. Finally, at altitude or with a fever, needs go up.

For example, an athlete who sweats a lot can lose 32 oz in an hour. So drink before, during and after the effort.

Water intake calculator: tap versus bottled water

Tap water in the United States is regulated and costs far less than bottled water. So it suits most adults. If the taste bothers you, let it rest in a chilled pitcher. In contrast, some mineral waters add calcium or magnesium that help with specific needs. For example, read the label to compare minerals.

Finally, skip very sugary drinks, because they add calories without hydrating better. A reusable bottle also cuts plastic waste and keeps water within reach.