Estimated Blood Volume (Nadler) Calculator

About this calculator

Nadler’s equations estimate total blood volume from height, weight and sex, since blood volume tracks body size more closely than weight alone: for men, Blood Volume (L) = 0.3669 x Height(m) cubed + 0.03219 x Weight(kg) + 0.6041; for women, Blood Volume (L) = 0.3561 x Height(m) cubed + 0.03308 x Weight(kg) + 0.1833. The cubic height term reflects that blood volume scales more closely with body volume than with a linear height measure.

Anesthesiologists and surgeons use estimated blood volume to calculate the maximum allowable blood loss during an operation before a transfusion is needed, and it’s a standard input when calculating transfusion requirements or dosing certain medications that are weight-and-volume dependent. It’s more accurate than the older, simpler rule of thumb (roughly 70 mL/kg for adults) because it accounts for body composition differences captured by height rather than weight alone.

This calculator takes your height, weight and sex and returns an estimated total blood volume using Nadler’s equations.