What formula does this blood volume calculator use?

It compares Nadler adult equations, a Lemmens-Bernstein-Brodsky estimate for higher BMI and a simple mL/kg method. The displayed recommended estimate depends on BMI in the tool.

Can this estimate actual blood loss?

No. It estimates total blood volume from body measurements. Actual blood loss depends on clinical assessment, measurements, vital signs, labs and the bleeding source.

Why enter hematocrit?

Hematocrit lets the tool split estimated total blood volume into plasma and red-cell portions. It does not make the total blood volume estimate a diagnosis.

Blood Volume Calculator

Estimate total blood volume with Nadler, Lemmens and mL/kg methods, plus plasma and red-cell volume from hematocrit.

Sex

Age

Body habitus

Height, cm

Weight, kg

Hematocrit, %

What this blood volume calculator estimates

This tool estimates total blood volume from height, weight, sex, age, body habitus and hematocrit. It compares Nadler, Lemmens and weight-based mL/kg estimates and then splits the selected estimate into plasma and red-cell volume.

B V_{ma l e} = 0.3669 H^{3} + 0.03219 W + 0.6041

Nadler adult male estimate, with height in meters and weight in kilograms.

B V_{L e mm e n s} = \frac{70 W}{B M I /22} \div 1000

Lemmens-Bernstein-Brodsky estimate used for higher BMI ranges.

Not a transfusion or bleeding calculator

Estimated blood volume is not the same as measured intravascular volume or actual blood loss. Do not use this page to decide on transfusion, fluids, emergency care or treatment.

How to interpret the result

Result	Meaning
Estimated blood volume	A model-based total blood volume estimate in liters and mL/kg.
Plasma volume	Estimated non-cellular portion based on hematocrit.
Red-cell volume	Estimated red-cell portion based on hematocrit.
Blood-loss classes	A percentage table for context, not a diagnosis of a real patient.

Seek urgent medical care for active bleeding, fainting, severe weakness, confusion, shortness of breath, cold clammy skin or suspected shock. A calculator cannot evaluate those situations.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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