Water Intake Calculator

This calculator can help you determine how much water you need to drink each day to avoid dehydration, but keep in mind that the amount you need can vary depending on things like how active you are, whether you‘re sick, and how much fluid is in your diet. Pregnant and breastfeeding women need to drink extra fluids to stay hydrated.

Water Intake calculator


You should drink ...... of water per day

Calculating the Ideal Daily Water Intake

The calculator will help you estimate your daily water needs, including how much you should drink in the form of fluids. The outputs are in liters, milliliters, cups, and ounces of water. These estimates are based on population averages, so you should consult your physician or nutritionist before making changes to your water consumption or exercise routine.

In order to estimate your recommended total daily water intake, you need to estimate your total daily energy expenditure (TDEE). This can be done by using a rule that expresses water needs in relation to energy requirements in ml/kCal. Energy requirements are based on extensive research in each age and gender group, taking into account body size and activity level. This research provides solid data for TDEE, rather than the compromise inherent in the Adequate Intake estimations made for water.


Those same determinants apply to water utilization and balance, providing an argument for linking water/fluid intake recommendations to the more thoroughly researched energy recommendations. The extent to which water intake requirements are determined by energy intake and expenditure is unknown, but it has long been practice in the clinical setting to provide 1 ml per kCal administered by tube to patients who are unable to take in food or fluids. This is the basis for the output of this daily water intake calculator.

Water Sources Within the Human Body

Water intake for the human body comes from three sources: water and other beverages, food, and as a sideeffect of metabolic processes. The calculator will output a total water intake recommendation as well as how much should be consumed through drinking fluids.

Be careful not to confuse how much water you need to drink with how much water you actually need. The latter is usually only around 4/5 of the total, so you need to drink slightly less water than your total daily needs. For example, if you need a total of 70 ounces per day, you would need to drink only 56 oz of water (7 cups, or roughly 7 standard water glasses). The rest will enter your body through food and metabolic processes.

Why Do We Have to Drink Water Frequently?

We need to drink fluids regularly to make up for the water our bodies constantly lose through various processes, such as urination, sweating, and respiration.

The human body needs to maintain homeostasis, and sweating helps to regulate body temperature. Depending on how active a person is and how hot their environment is, they may need to drink different amounts of water. Other factors that can affect how much water a person needs to drink are living in a climate that is too hot or too cold, or being pregnant.

Recommendations for General Water Consumption

Water consumption is shown in L/day (litres per day) in the table. For comparison, one litre is roughly equal to four standard water glasses.

Age groupTotal water intakeFluid intake
0-6 mo.0.68 (milk)0.68 (milk)
6-12 mo.0.80 – 1.000.64 – 0.80
1-2 years1.10 – 1.200.88 – 0.90
2-3 years1.31
1-3 yearsN/AN/A
4-8 years1.61.2
9-13 y. Boys2.11.6
9-13 y. Girls1.91.5
Boys 14+ & Adult Men2.52
Girls 14+ & Adult Women21.6
Pregnant Women2.31.84
Lactating Women2.62.1
ElderlyAs adultsAs adults

It‘s important to remember that, in most cases, our bodies are pretty good at knowing how much water we need each day. Thirst is usually a good indicator of how much water we need to drink.

Adjustments According to the Climate, Excessive Sweating & Pregnancy

If you are a woman, you will require more water per day if you are pregnant or lactating. Our water drinking calculator will perform the adjustments for you based on a compromise between tables provided.

This calculator is only accurate for people who spend most of their time in moderate climates. If you live in a hot climate and are mostly exposed to the sun or in a nonclimatized building, then you will need to drink more water than what is suggested. However, there is no good research that estimates how much more water you should drink in these conditions.

The hydration calculator results assume that you are not doing any vigorous physical activity in a hot environment. If you are, you could lose more than 3L of fluid per hour, and you would need to drink more fluids to make up for that. Cold climates don‘t have as much of an effect, but if it‘s extremely cold, you might need more water because you use up more energy to stay warm,

The Advantages of Staying Hydrated

The water intake calculator is important because it helps maintain a healthy life, but water is also linked to benefits for the treatment of health conditions and mental state improvement.

Kidney function

An abundant water supply helps the kidneys function more efficiently. If the kidneys don‘t have enough water, they produce a more concentrated urine. This costs more energy and can damage the kidneys. Drinking enough water can help protect the kidneys from stress.

Good hydration reduces the likelihood of kidney stones recurring, so it‘s a good idea to use a daily water intake calculator to estimate how much water you need to drink each day.

Athletic performance

It is not uncommon for athletes to lose 610% of their body weight in sweat during challenging athletic events, which can lead to dehydration if fluids have not been adequately replenished. Much lower levels of dehydration can result in decrements in physical performance for athletes, as little as 2%. Rehydration can reverse these deficits, and also reduce oxidative stress induced by exercise and dehydration. Hypohydration appears to have a more significant impact on highintensity and endurance activity than on anaerobic activities or shorterduration activities.

Children are more likely than adults to become dehydrated, so it‘s important for children who play sports or are in hot climates to start each day wellhydrated.

Cognitive Skills

A number of studies have been conducted to examine the effects of dehydration on cognitive performance. However, it is difficult to determine the exact effects of dehydration on cognition because many of the studies use different methodologies and measure different cognitive behaviors. It is also difficult to determine the effects of dehydration on cognition in temperate conditions because most of the studies that have been conducted have induced dehydration by combining heat and exercise. However, it is believed that mild dehydration acts as a physiological stressor which competes with and draws attention from cognitive processes.

A study done more recently concluded that even a body water loss of 12% can impair cognitive performance, even though it was traditionally thought that a 2% or more body water deficit was needed to produce cognitive performance decrements. This means that it is important to tell clients about the importance of water for normal body functioning and its effects on physical and cognitive performance when discussing their health.

Type II Diabetes

Research has shown that people who drink less water are more likely to be diagnosed with hyperglycemia, and a study has confirmed that three days of drinking less water can make blood sugar levels worse in people with type 2 diabetes mellitus.

Constipation and Water Consumption

The causes of constipation, which is characterized by slow gastrointestinal transit, small, hard stools, and difficulty in passing stool, include medication use, inadequate fiber intake, poor diet, and illness. Although it is commonly believed that inadequate fluid consumption is a common cause of constipation and that increasing fluid intake is a frequently recommended treatment, the evidence suggests that increasing fluids is only of usefulness in individuals in a hypohydrated state and is of little utility in properly hydrated people. In young children with chronic constipation, increasing daily water intake by 50% did not affect constipation scores.

Blood Pressure and Heart Rate

Water intake has a number of benefits for people with normal or increased blood pressure, including reducing heart rate and increasing blood pressure. These effects can be observed within 1520 minutes of drinking water, and can last for up to 60 minutes. Water intake is also beneficial in preventing vasovagal reactions and syncope in blood donors who are at high risk for postdonation syncope. Therefore, it is advisable to use a water intake calculator and to try to stick to the estimate as closely as possible.

Bronchopulmonary Conditions

There is evidence that exerciserelated asthma is linked with low fluid intake, and that increasing water intake can help improve the condition.

Skin and Skin Problems

There is no evidence that increasing the amount of water you drink will have any impact on the complexion of your skin, remove wrinkles, or help with acne or other skin conditions. Water intake per day will improve the skin thickness and density.

Weight Loss Through Increased Water Consumption?

A 2014 study of 50 overweight women found that drinking 1.5 liters of water above the recommended daily amount, three times a day, 30 minutes before meals, resulted in weight loss, reduced BMI, and reduced appetite scores over an 8week period. This suggests that increased water drinking can lead to weight loss, body fat reduction, and appetite suppression.

Water Content in Different Foods

Water percentageFood item
Fat-free milk, cantaloupe, strawberries, watermelon, lettuce, cabbage, celery, spinach, pickles, squash (cooked)
Fruit juice, yogurt, apples, grapes, oranges, carrots, broccoli (cooked), pears, pineapple
Bananas, avocados, cottage cheese, ricotta cheese, potato (baked), corn (cooked), shrimp
Pasta, legumes, salmon, ice cream, chicken breast
Ground beef, hot dogs, feta cheese, tenderloin steak (cooked)
Cheddar cheese, bagels, bread
Pepperoni sausage, cake, biscuits
Butter, margarine, raisins
Walnuts, peanuts (dry roasted), chocolate chip cookies, crackers, cereals, pretzels, taco shells, peanut butter
0%Oils, sugars
1 rep max
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