How many liters is equal to 1 unit of blood?

This question needs more information. 1 unit of blood can be a couple of different things. It could be whole blood or packed cells. I will assume whole blood is what is being asked. A unit of blood is never the same. It is approximately 450 ml's. So your answer would be simply 0.45 liters. As a nurse, I have hung hundreds of units of blood for patients and they are all different. We record the amount of volume in each bag when given to a patient. But typically blood given to patients is given in components. They are given either packed cells which are just the red cells to transport oxygen or they are given plasma for volume or platelets for clotting factors. Typically the blood is spun at the blood bank and separated out. Depending on the volume of packed cells spun off is how much is given to patients in the hospital.