I am attaching 2 Excel spreadsheets - one on "How Much water is required by your body" and another on the "Ideal Weight" based on height.
Hope you find it useful
Note: these are not created by me but got as forward in email from a friend !
Out of the two attachments, the one titled as 'ideal Weight' gives fairly reliable results but the 'water requirement calculator' doesn't fit well especially when used to calculate the water requirement of kids.
The amount of water that the kids normally require is much more than the figure it generates based on the overall body weight of the individual. In addition, compared to adults, the frequency of water intake for kids is also higher for the simple fact that they are more active, grow faster and thus their rate of metabolism is considerably higher.
One thing that too I'm not sure about is whether the value generated by the calculator is for pure water or it's the total water intake in all forms; i.e. through milk, juice, food, fruits etc. For a kid weighing 10 kg, it calculates 330 ml of water/ day while in practice, the total daily requirement of this age group comes out to be around 1.50 Ltrs. (water in all forms).
Whatever I said here is simply based on my observations and the exercises I did with the attachment. However, it works fairly well with the adults.
Thanks.