How much water is in the adult human body?

How much water is in the adult human body?

• A. 25 litres
• B. 50 litres
• C. 75 litres
• D. 100 litres

Answer: (B)

Total body water is a large, but not unlimited, part of our body—the body is about 60% water by weight. In a typical adult around 70 kg, that amounts to roughly 42 litres. Water is split mainly into two compartments: inside cells (intracellular) and outside cells (extracellular), with about two-thirds inside and one-third outside. For simplicity in exams, this total is often rounded to about 50 litres. The other options are too low or too high for an average adult, so 50 litres is the best rounded estimate.

Total body water is a large, but not unlimited, part of our body—the body is about 60% water by weight. In a typical adult around 70 kg, that amounts to roughly 42 litres. Water is split mainly into two compartments: inside cells (intracellular) and outside cells (extracellular), with about two-thirds inside and one-third outside. For simplicity in exams, this total is often rounded to about 50 litres. The other options are too low or too high for an average adult, so 50 litres is the best rounded estimate.