Blood Volume Calculator

Our blood volume calculator calculates the total blood volume using three different techniques. The first employs Dr. Nadler’s equation, while the second makes use of an equation created by Drs. Lemmens, Bernstein, and Brodsky. You can locate a straightforward technique in advanced mode that provides a more insightful alternative to the first two.

For patients having surgery, estimating the anticipated blood volume (BV) is crucial. It affects hemodynamic and pharmacologic treatments, as well as transfusion procedures, in perfusion care (see our blood donor calculator). To learn how blood volume impacts blood pressure, continue reading.

Please be aware that this is an adult blood volume calculator. Use our pediatric blood volume calculator to estimate a child’s blood volume.

Blood Volume Calculator

How does this blood volume calculator work?

The liquid (plasma; find out more with our fresh/frozen plasma dosage calculator) and cellular components of blood volume make up the total volume. There are several ways to directly or indirectly quantify blood volume, but they are all impractical for everyday clinical use.

In individuals of normal weight, the mean indexed blood volume (iBV) is 65 mL/kg for women and 70 mL/kg for men. The option to compute it in this manner may be found in advanced mode.

This number cannot be utilized for individuals who are obese or severely obese since iBV drops in a non-linear manner as weight increases. The techniques for calculating total blood volume that we present here cater for a wide variety of body weights.

Nadler’s Equation for total blood volume – Method 1

Dr. Allen created a sophisticated algorithm to determine blood volume in 1956.

Dr. Nadler discovered more precise coefficients in 1962, building on Dr. Allen’s research, and he published the equation in his essay Prediction of blood volume in normal human adults.

Our blood volume estimator use the following formula:

Our blood volume calculator uses this formula:

Lemmens-Bernstein-Brodsky equation for estimated blood volume – Method 2

In 2006, Dr. Lemmens, Dr. Bernstein, and Dr. Brodsky discovered an equation that allows physicians to predict ᵢBV over the full spectrum of body weights and body mass indices (BMI) in patients unstressed by acute trauma or critical illness.

The blood volume calculator uses this formula:


How does blood volume affect blood pressure?

Factors that affect blood pressure (BP) are interconnected:

  • Peripheral resistance – the constriction of the arteries elevates the BP. Peripheral resistance also includes: vessel length, blood viscosity, and arterial stenosis;
  • Total blood volume; and
  • Cardiac output (discover more with our stoke volume calculator).