The Total Body Water (TBW) Calculator is a valuable tool used in clinical practice to estimate the amount of water in a patient’s body. This is a critical metric for a variety of medical applications, including determining fluid replacement needs, guiding medication dosing for drugs that distribute in body water, and assessing nutritional status. The calculator below uses the widely cited Watson formula, which incorporates a patient’s age, weight, height, and gender to provide a more accurate estimate of TBW than simpler methods, aiding clinicians in making more precise and personalized treatment decisions.

References:

• Watson, P. E., Watson, I. D., & Batt, R. D. (1980). Total body water volumes for adult males and females estimated from simple anthropometric measurements. The American Journal of Clinical Nutrition, 33(1), 27-39.
• O’Driscoll, T. M., & L’Estrange, J. J. (1993). Predictive equations for total body water: validation with bioelectrical impedance analysis and dilution methods. The American Journal of Clinical Nutrition, 58(1), 11-16.