The term human blood volume refers to the total amount of fluid circulating within arteries, capillaries, veins, venules, and chambers of the heart at any time. The amount of blood circulating within a healthy individual depends on size and weight and can be estimated with a simple blood volume calculator.
The average male adult has approximately 5.5 liters of blood circulating and the average female adult approximately 4.5 liters. During pregnancy, a woman may have up to 50% more blood. The components of blood are red and white blood cells as well as blood plasma.
Blood volume is tightly regulated and related to multiple organ systems. The maintenance of blood volume is crucial to the normal function of the human body. Blood volume can be increased or decreased by systemic illnesses such as kidney disease, heart failure, or other types of diseases affecting the circulatory system.