Total Body Water Calculator

What Is Total Body Water?

Total body water (TBW) is the volume of water in your body, including intracellular and extracellular fluid. It is usually reported in liters and as a percentage of body weight. Hydration planning pairs well with the Water Intake Calculator and Body Fat Calculator.

Watson Formula

For men:

$$\text{TBW (L)} = 2.447 - 0.09156 \times \text{age} + 0.1074 \times \text{height (cm)} + 0.3362 \times \text{weight (kg)}$$

For women:

$$\text{TBW (L)} = -2.097 + 0.1069 \times \text{height (cm)} + 0.2466 \times \text{weight (kg)}$$

Typical Ranges

Healthy adults often fall near 58% ± 8% for men and 48% ± 6% for women, though individual variation is normal. Muscle tissue holds more water than fat tissue.