Plasma Volume Calculator

Estimate plasma volume — the liquid fraction of your blood — from total blood volume and hematocrit, or directly with the published Kaplan and Hakim formulas. Also shows ideal plasma volume and plasma volume status (PVS).

Educational estimate only. This tool is not a medical device and is not medical advice. Fluid resuscitation, transfusion, diuretic therapy and any clinical decision must be made by qualified clinicians.

Mode 1 — From total blood volume

Plasma volume = blood volume × (1 − hematocrit).


Formulas used

Frequently asked questions

What is plasma volume?
Plasma volume is the volume of the liquid part of your blood. Plasma carries red cells, white cells and platelets, and it makes up roughly 55 percent of total blood volume in a healthy adult. It is reported in liters or milliliters.
How is plasma volume calculated from blood volume?
Plasma volume equals total blood volume multiplied by one minus the hematocrit fraction: PV = BV x (1 - Hct). With hematocrit in percent, that is PV = BV x (100 - Hct) / 100. For example, 5.0 L of blood at 45 percent hematocrit gives 2.75 L of plasma.
What is the Kaplan formula for plasma volume?
The Kaplan formula estimates plasma volume from body weight and hematocrit only: PV (mL) = 0.065 x weight in kg x (1 - hematocrit) x 1000. A 70 kg person with 45 percent hematocrit gets about 2502.5 mL.
What is the Hakim formula for plasma volume?
The Hakim formula is PV (mL) = (1 - hematocrit) x [a + b x weight in kg], with a = 1530 and b = 41 for men, and a = 864 and b = 47.9 for women. A 70 kg man with 45 percent hematocrit gets 2420 mL.
What is ideal plasma volume?
Ideal plasma volume is the expected normal value for a body weight: iPV (mL) = c x weight in kg, with c = 39 for men and c = 40 for women. A 70 kg man has an ideal plasma volume of 2730 mL.
What is plasma volume status (PVS)?
Plasma volume status compares an estimated plasma volume against the ideal value: PVS (%) = (estimated PV - ideal PV) / ideal PV x 100. A value above +10 percent counts as above the expected range.
What is a normal plasma volume?
Published estimates put normal plasma volume around 30 to 45 mL per kg of body weight in healthy adults, roughly 2.5 to 3 liters for a 70 kg person. This tool also reports your result in mL/kg and as plasma volume status versus the ideal value.
Kaplan or Hakim: which estimate should I use?
Kaplan needs only weight and hematocrit, so it is the simpler of the two. Hakim adds sex-specific constants and usually lands close to Kaplan. Treat both as rough estimates, not measurements.
How is this different from the blood volume calculator?
The blood volume calculator estimates TOTAL blood volume with the Nadler or Gilcher formulas and has no hematocrit input. This tool takes the extra step of multiplying by (1 - hematocrit) to isolate the plasma fraction, or uses the Kaplan and Hakim direct formulas.
Is this medical advice?
No. This calculator gives educational estimates from published equations. It is not a medical device and not medical advice. Fluid management, transfusion and diuretic decisions must be made by qualified clinicians.
Related tools: Blood Volume Calculator FFP Dose Calculator Plasma Osmolality Calculator

Free tool by NRTechStudio

⚡ Related Utility Tools

Explore similar finance tools and calculators. 100% free, accurate, and runs completely in your browser without sign-up.

Finance Free & Private

Gross Margin Calculator — Free

Free gross margin calculator: Rp & percent margin, markup conversion, 3-way target margin solver, A vs B comparator, COGS scenario table. 100% in-browser.

Launch Calculator →
Finance Free & Private

Gross Pay Calculator — Hourly, Salary, Overtime, Bonus, Commission & Tips

Free gross pay calculator: compute gross wages from hourly rate × hours, overtime at 1.5× (FLSA), double time, salary, bonuses, commissions and tips — shown weekly, biweekly, monthly and annually.

Launch Calculator →
Finance Free & Private

Property GRM (Gross Rent Multiplier) Calculator — Free

Free property GRM calculator: compute gross rent multiplier from price and rent, implied price/rent solver, compare 2 properties, GRM vs rental yield.

Launch Calculator →
Finance Free & Private

Growing Annuity Calculator — PV, FV & Solver

Free growing annuity calculator: present value & future value of payments growing g% per period, PMT1/g/r/n solver, growing vs level annuity comparison.

Launch Calculator →
Finance Free & Private

India GST Calculator — Calculate CGST, SGST & IGST (Add, Remove, Compare)

India GST calculator: add GST to base price, remove GST from inclusive price, compare two rates, find effective rate. CGST/SGST/IGST split. Free.

Launch Calculator →
Finance Free & Private

GST QST Calculator Quebec — 5% GST + 9.975% QST (2026)

Free GST QST calculator for Quebec: add or remove 5% GST + 9.975% QST from any price. Exact breakdown, reverse tax calculator, and Canada province comparison.

Launch Calculator →
Browse All Finance Tools (356) → Master Directory (2,700+ Tools)