What is the approximate blood volume in an average adult?

What is the approximate blood volume in an average adult?

• A. 4.5 liters
• B. 5.7 liters
• C. 6.8 liters
• D. 7.0 liters

Answer: (B)

Blood volume in an average adult is about five liters, roughly 70 mL per kilogram of body weight. For a typical 70 kg person, that works out to about 4.9 L, and exam-style figures often round this to around 5 L. In many medical references, a range around 5–6 L is used for an average adult, so 5.7 L is a reasonable, commonly cited approximation. The smaller value would fit a smaller individual, while the larger values are high for an average adult. So 5.7 liters best matches the standard approximation.

Blood volume in an average adult is about five liters, roughly 70 mL per kilogram of body weight. For a typical 70 kg person, that works out to about 4.9 L, and exam-style figures often round this to around 5 L. In many medical references, a range around 5–6 L is used for an average adult, so 5.7 L is a reasonable, commonly cited approximation. The smaller value would fit a smaller individual, while the larger values are high for an average adult. So 5.7 liters best matches the standard approximation.