# How to Determine How Much Water to Drink [closed]

I am planing to develop a mobile application to monitor the water intake level of a person. I found the following calculator, but I have no idea what is the formula that they have used in the calculator.

https://www.gigacalculator.com/calculators/water-intake-calculator.php

I want to create a formula to determine how much water to drink per day using following inputs.

• Age
• Weight
• Height
• Gender
• Activity(No of hours)

Can any one suggests me a formula for this

• The formula is: "When you are thirsty, drink some water.". That's far more reliable than any calculations you can make. A slight improvement would be to add: "If you've been sweating, add a pinch of salt to it." Apr 7 '20 at 0:44
• It's like you asked Newton why you didn't eat the apple instead of finding a formula. You live in 21st century Apr 7 '20 at 5:52
• Whatever formula that website uses, it's wrong. The site asks about exercise on a per-week basis, while hydration level fluctuates on a timescale of less than a day. (It also asks how often you exercise, when it should be asking how hard you exercise.)
– Mark
Apr 8 '20 at 0:27

No, because activity as a feature is too highly variant and there are probably a lot of other factors that would go into a formula like this.

If you do a bit of research you will find that there are guidelines of fluid intake per day for certain groups of patients, e. g. in intensive care, dialysis patients,...: https://www.ncbi.nlm.nih.gov/pubmed/?term=fluid+intake+per+day

The first hit on "formula fluid intake per day" produces a hit from the Daily Mail (https://www.dailymail.co.uk/femail/food/article-4617270/How-water-REALLY-drink-day-revealed.html), which does not have too high of an impact factor.

The "8 glasses of water per day" rule is a one-size-fits-all rule that should not be used on people with e. g. organ damage such as heart failure, renal failure etc.

• I want to develop a similar calculator like this. gigacalculator.com/calculators/water-intake-calculator.php . Apr 6 '20 at 18:41
• @AmilaDulanjana Ambient temperature and humidity are potentially huge factors and you're ignoring them. The amount of water you need on a winter day in Norway wouldn't keep you alive in the Sahara desert on a summer day. As I said in my comment on your question, you need to do a little research on your own and add what you find to your question. Apr 6 '20 at 19:33
• I don't understand why do you want to make this solution more complicated. This is a MVP solution and we can include these features later. Moreover any one knows how to calculate the BMI index of a person, but it's not accurate. But everyone is using it to get an idea. So if you dont know the real answer it's better not to give opinion like this. Apr 7 '20 at 5:56
• @AmilaDulanjana, if you don't include those complexities, your minimum product won't be viable.
– Mark
Apr 8 '20 at 0:19