Hume and Weyers developed equations for predicting total body water based on the patient's gender and body surface area.
For males:
body surface area in square meters =
= (0.036377 * (total body water in liters)) + 0.3539
This can be rewritten, as
total body water in liters =
= (27.4899 * (body surface area in square meters) - 9.728675
For females:
body surface area in square meters =
= (0.04737 * (total body water in liters)) + 0.1780
This can be rewritten, as
total body water in liters =
= (21.110407 * (body surface area in square meters) - 3.75765