A statistical analysis of 250 donor units of whole blood for net weight, hematocrit, specific gravity, erythrocyte volume and weight, plasma acid-citrate-dextrose volume and weight, leukocyte count (per cu. mm.), and absolute leukocyte content (per unit) was undertaken. Using net weight and hematocrit of the donor unit, formulas are derived for all of the above. Tables and graphs that provide each parameter for an individual donor unit when the net weight, hematocrit, and leukocyte count are known are included.