Free Water Calculator

Formula

The formula to calculate the Free Water Needed Per Day (FW) is:

\[ FW = (BW \times 0.033) + (E \times 0.001) \]

Where:

\( FW \) is the amount of free water needed per day (liters)
\( BW \) is the body weight (kg)
\( E \) is the amount of extra water needed due to exercise or hot weather (minutes of exercise or degrees above 20°C)

Free Water (FW): The amount of water that is not bound in a substance and can be removed through processes like drying or heating.
Body Weight (BW): The weight of a person in kilograms.
Extra Water Needed (E): The additional water required due to exercise or hot weather, measured in minutes of exercise or degrees above 20°C.

Let's say the body weight (BW) is 70 kg and the extra water needed (E) is 30 minutes of exercise. Using the formula:

\[ FW = (70 \times 0.033) + (30 \times 0.001) \]

We get:

\[ FW = 2.31 + 0.03 = 2.34 \text{ liters} \]

So, the amount of free water needed per day is approximately 2.34 liters.