Total Blood Volume Calculator (Nadler's Equation)
Calculate circulating blood volume, plasma, and red blood cell mass using Nadler's Equation. Essential for hematology and surgical planning.
About
Accurate estimation of total blood volume (TBV) is vital in clinical settings involving major surgery, treatment of severe burns, or management of congestive heart failure. While standard references often cite an average of 5 liters for adults, individual variance based on body surface area is significant. Miscalculation can lead to improper fluid resuscitation or transfusion errors.
This tool utilizes Nadler's Equation, the gold standard in hematology, to derive TBV based on height and weight. Unlike simple weight-based estimates (e.g., 70 ml/kg), Nadler's formula accounts for the non-linear relationship between body composition and vascular capacity. Additionally, by inputting a Hematocrit level, this calculator separates the total volume into its constituent parts: Plasma Volume (PV) and Red Blood Cell Volume (RCV), providing a granular view of hematologic status.
Formulas
We utilize Nadler's Equation, which provides higher precision than the Gilcher's Rule of Five. The formulas differ by biological sex.
Nadler's Equation for Males:
Nadler's Equation for Females:
Where H is height in meters and W is weight in kilograms. Plasma and RBC volumes are derived using Hematocrit (Hct):
Reference Data
| Subject / Condition | Average Volume (mL/kg) | Total Volume (Typical 70kg) | Plasma % (Approx) | RBC % (Approx) |
|---|---|---|---|---|
| Neonate (Pre-term) | 90 - 100 | 0.25 L | 45% | 55% |
| Neonate (Term) | 80 - 90 | 0.3 L | 40% | 60% |
| Infant (3 months) | 70 - 80 | 0.5 L | 55% | 45% |
| Child (1 year) | 70 - 75 | 0.7 L | 60% | 40% |
| Adult Male (Muscular) | 75 | 5.25 L | 55% | 45% |
| Adult Male (Average) | 70 | 4.9 L | 58% | 42% |
| Adult Male (Obese) | 60 | 5.5 L | 60% | 40% |
| Adult Female (Average) | 65 | 3.9 L | 62% | 38% |
| Adult Female (Pregnant) | 90 - 100 | 5.5 L | 65% | 35% |
| Adult Female (Obese) | 55 | 4.5 L | 62% | 38% |
| Elderly (>75 yrs) | 60 - 65 | 4.2 L | 60% | 40% |
| Athlete (Endurance) | 85 | 6.0 L | 58% | 42% |