The percentage of water varies according to our age and gender.

The amount of water in the human body ranges from 50-75%. The average adult human body is 50-65% water, averaging around 57-60%. The percentage of water in infants is much higher, typically around 75-78% water, dropping to 65% by one year of age.

Body composition varies according to gender and fitness level, because fatty tissue contains less water than lean tissue. The average adult male is about 60% water. The average adult woman is about 55% water because women naturally have more fatty tissue than men. Overweight men and women have more water, as a percent, than their leaner counterparts.

The percent of water depends on your hydration level. People feel thirsty when they have already lost around 2-3% of their body's water. Mental performance and physical coordination start to become impaired before thirst kicks in, typically around 1% dehydration.

Although liquid water is the most abundant molecule in the body, additional water is found in hydrated compounds. About 30-40% of the weight of the human body is the skeleton, but when the bound water is removed, either by chemical desiccation or heat, half the weight is lost.