The average adult human carries roughly five liters of blood. This number fluctuates depending on height, weight and muscle mass.
This five-liter average is estimated for a standard adult male weighing 160 pounds. The volume of blood in a person is roughly one-eleventh of his body weight. There is some evidence that people at higher altitudes may have more blood than average to make up for the lack of oxygen in the atmosphere. Although there are four different blood types, type has no correlation with the amount of blood in a body.