Plasma Volume Calculator — Blood Plasma Estimation
Estimate your plasma volume — the liquid fraction of blood — from height, weight and hematocrit using the clinically established Nadler formula.
Biological sex
cm
kg
%
Estimated liquid fraction of total blood volume (Nadler formula)
- 1
Height in metres
175 cm ÷ 100 = 1.75 - 2
Height cubed
1.75³ = 5.359375 - 3
Total blood volume (Nadler)
(0.3669 × 5.3594 + 0.03219 × 70 + 0.6041) × 1000 = 4,824 mLSex-specific Nadler regression, result converted to mL. - 4
Plasma fraction
1 − 42 ÷ 100 = 0.58 - 5
Plasma volume
4,824 × 0.58 = 2,798
How does this calculator work?
Plasma volume is estimated by first computing total blood volume with the Nadler formula (e.g. TBV = 0.3669×h³ + 0.03219×w + 0.6041 for men, h in metres, w in kg), then multiplying by (1 − hematocrit). A typical healthy adult plasma volume is 2,500–3,500 mL, or roughly 40–50 mL/kg.
Formula
How this is calculated
The calculator uses the Nadler (1962) regression equations to estimate total blood volume (TBV) from height and weight, then partitions it using the hematocrit. The Nadler formula was derived from dye-dilution measurements on a broad population sample and is the most widely cited non-invasive equation for blood volume estimation. Height appears cubed (h³) because blood volume correlates closely with lean body mass, which scales roughly with the cube of stature. Sex-specific coefficients account for the body-composition difference between men and women.
Once TBV is known, plasma volume = TBV × (1 − Hct/100) and red cell volume = TBV × Hct/100, where hematocrit (Hct) is the percentage of whole blood occupied by red cells. In a typical healthy adult, plasma accounts for about 55% of blood volume. Normal resting plasma volume is roughly 40–50 mL/kg in men and 36–45 mL/kg in women.
Limitations: this is a statistical estimate, not a direct measurement. It assumes typical adult body composition and loses accuracy for extreme obesity, dehydration, pregnancy, or disease states that alter plasma expansion. For clinical decisions, direct measurement by isotope-dilution (e.g. ¹²⁵I-albumin or ⁵¹Cr-labelled red cells) remains the reference standard.
Frequently asked questions
Plasma is the pale-yellow, protein-rich liquid fraction of blood that carries nutrients, hormones, clotting factors and waste products. Plasma volume determines blood pressure, cardiac output and fluid balance, and is a key variable in exercise physiology, anaemia assessment and clinical fluid management.
Published in 1962, the Nadler formula estimates total blood volume from height (cubed) and body weight using sex-specific regression coefficients derived from radio-isotope dilution studies. It is the most widely used equation for non-invasive blood volume estimation in clinical research.
Hematocrit is part of a routine blood count (CBC/FBC). Typical reference ranges are 38–52% for adult men and 35–47% for adult women. If you do not have a recent lab result, enter the midpoint of the typical range for your sex as an estimate.
Also known as
TG we-Calculate Editorial Team. (2026). Plasma Volume Calculator — Blood Plasma Estimation [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/plasma-volume-calculator
TG we-Calculate Editorial Team. "Plasma Volume Calculator — Blood Plasma Estimation." TG we-Calculate. 2026. https://we-calculate.com/calculator/plasma-volume-calculator.
TG we-Calculate Editorial Team, "Plasma Volume Calculator — Blood Plasma Estimation," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/plasma-volume-calculator
@misc{wecalculate_plasma_volume_calculator, title = {Plasma Volume Calculator — Blood Plasma Estimation}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/plasma-volume-calculator}}, year = {2026}, note = {TG we-Calculate} }
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