Estimate total blood volume with the Nadler formula (sex + height + weight), compare against the simpler Gilcher rule of fives, and see what a 500 mL blood donation means as a share of your total.
Please enter a valid height (0.5-2.6 m / 50-260 cm) and weight (25-400 kg).
Nadler estimate:
Gilcher comparison:
Share of body weight:
One 500 mL donation is: of total blood volume
Nadler: men BV (L) = 0.3669 × height(m)3 + 0.03219 × weight(kg) + 0.6041; women BV (L) = 0.3561 × height(m)3 + 0.03308 × weight(kg) + 0.1833 (Nadler, Hidalgo & Bloch, Surgery 1962).
Gilcher rule of fives (normal build): 70 mL/kg for men, 65 mL/kg for women.
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Nadler, Hidalgo and Bloch derived blood volume from radioisotope measurements in normal adults (Surgery, 1962). Height must be in meters and weight in kilograms; the result is in liters:
| Sex | Formula (liters) | Coefficients |
|---|---|---|
| Men | BV = 0.3669 x H^3 + 0.03219 x W + 0.6041 | H in meters, W in kg |
| Women | BV = 0.3561 x H^3 + 0.03308 x W + 0.1833 | H in meters, W in kg |
A simpler bedside alternative estimates blood volume per kilogram of body weight, adjusted for build:
| Build | Men (mL/kg) | Women (mL/kg) |
|---|---|---|
| Thin | 65 | 60 |
| Normal | 70 | 65 |
| Muscular | 75 | 70 |
| Obese | 60 | 55 |
Note: this is an educational estimate, not a measurement. Accuracy drops with obesity, pregnancy, anemia, critical illness and in children. Clinical decisions such as transfusion or fluid resuscitation must be made by qualified clinicians.
The Nadler formula (Nadler, Hidalgo & Bloch, 1962) estimates blood volume from sex, height and weight. For men BV (L) = 0.3669 x height(m)^3 + 0.03219 x weight(kg) + 0.6041; women BV (L) = 0.3561 x height(m)^3 + 0.03308 x weight(kg) + 0.1833.
Nadler's equation was derived from radioisotope measurements in normal adults and is still the most widely used bedside estimator, including in apheresis machines. It is an estimate, not a measurement: accuracy drops with obesity, pregnancy, anemia, critical illness and in children.
Gilcher's rule of fives is a simpler alternative that estimates blood volume per kilogram of body weight. For a normal build: 70 mL/kg for men and 65 mL/kg for women. Variants exist for other builds (men: thin 65, obese 60, muscular 75 mL/kg; women: thin 60, obese 55, muscular 70 mL/kg).
About 4.5-5.5 liters for men and 3.5-4.5 liters for women, roughly 7-8% of body weight. A 70 kg man is typically estimated at 4.8-4.9 L.
Height in meters and weight in kilograms, giving blood volume in liters. Convert first: 5 ft 9 in = 1.75 m, 154 lb = 70 kg.
Common uses include apheresis and blood donation planning, estimating allowable blood loss in surgery, dosing weight-based drugs, and assessing fluid resuscitation needs.
An alternative for obese patients: BV = 70 x sqrt(weight/70) ... actually the Lemmens-Bernstein-Brodsky equation adjusts for body composition in obesity where Nadler overestimates. It is used in bariatric anesthesia.
Yes, plasma volume expands 40-50% by the third trimester, which is why standard formulas do not apply to pregnant patients.
Formulas estimate normal blood volume; they cannot detect acute dehydration or bleeding. A dehydrated patient has less circulating volume than the formula predicts.
Blood volume is the total (plasma + red cells). Plasma is about 55% of blood volume. Formulas like Nadler estimate total blood volume.
No, it was derived in adults. Pediatric estimates use weight-based rules (e.g. 70-80 mL/kg depending on age) under clinician supervision.
Body composition differs: men average more muscle and less adipose tissue per kilogram, and since blood volume tracks lean mass, sex-specific coefficients fit the data better.
Roughly 65-75 mL/kg in adults: about 70 mL/kg for men and 65 mL/kg for women of normal build per Gilcher's rule.
One liter is about 2.11 US pints. A 4.82 L blood volume is roughly 10.2 pints.
No. It is an educational tool. Clinical decisions such as transfusion or fluid resuscitation must be made by qualified clinicians.
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