Enter the hematocrit level and total blood volume into the calculator to determine the plasma volume; this calculator can also evaluate any of the variables given the others are known.

Plasma Volume Formula

The following formula is used to calculate the plasma volume:

PV = (Hct * TBV) / (1 - Hct)


  • PV is the plasma volume
  • Hct is the hematocrit level
  • TBV is the total blood volume

To calculate the plasma volume, multiply the hematocrit level by the total blood volume, then divide the result by 1 minus the hematocrit level.

What is a Plasma Volume?

Plasma volume refers to the amount of plasma, the liquid component of blood, circulating in the body. Plasma makes up about 55% of total blood volume and is composed primarily of water, but also contains proteins, glucose, clotting factors, electrolytes, hormones, carbon dioxide, and oxygen. It plays a crucial role in maintaining blood pressure and regulating body temperature. Plasma volume is typically measured in milliliters and can vary depending on a person’s size, hydration level, and overall health. For example, an average-sized adult male may have a plasma volume of approximately 3,000 milliliters. Changes in plasma volume can indicate various health conditions, such as dehydration, kidney disease, or heart failure.

How to Calculate Plasma Volume?

The following steps outline how to calculate the Plasma Volume.

  1. First, determine the hematocrit level (%). 
  2. Next, determine the total blood volume (TBV) in liters. 
  3. Next, gather the formula from above = Plasma Volume = TBV * (1 – hematocrit/100).
  4. Finally, calculate the Plasma Volume.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

hematocrit level (%) = 45

total blood volume (TBV) in liters = 5