Estimated Plasma Volume Calculator

About this calculator

The Kaplan-Hakim formula estimates plasma volume from routine blood values: Plasma volume (mL) = (1 − hematocrit) × [a + (b × weight in kg)], with sex-specific constants. From that estimate, estimated Plasma Volume Status (ePVS) compares the calculated volume against an “ideal” plasma volume derived from body weight, giving a percentage that indicates whether a patient is volume-overloaded (congested) or volume-depleted.

Cardiologists use ePVS specifically in heart failure management, where it has emerged as a useful, calculation-only marker of congestion — since it's derived entirely from a standard complete blood count (hematocrit, hemoglobin) and body weight, it doesn't require the invasive or expensive testing that direct plasma volume measurement would, making it practical to track at every clinic visit or hospital admission.

This calculator takes body weight, hematocrit and hemoglobin and returns the estimated plasma volume and plasma volume status.