The estimation of surgical blood loss, particularly after large blood loss cases, by anesthesia personnel can be subjective and can vary between individuals. Intraoperative transfer of anesthesia care also affects blood loss estimates. This manuscript proposes a simple objective methodology to estimate surgical blood loss that does not depend upon any individual and can easily be calculated from knowledge of the patient’s sex, height and weight, the starting hemoglobin (or hematocrit), the ending hemoglobin (or hematocrit), the number of packed red blood cells and whole blood units transfused, and the volume of cell saver blood reinfused.