Blood Volume Calculator

Enter your sex, height, and weight to estimate your total blood volume. The Blood Volume Calculator uses the Nadler formula to calculate estimated blood volume in liters and milliliters, along with red blood cell volume and plasma volume breakdowns based on your hematocrit.

Disclaimer: This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any health-related decisions.

Sex *

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Normal range: 37–52% for men, 36–48% for women.

Results

Estimated Total Blood Volume

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Total Blood Volume (mL)

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Plasma Volume

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Red Blood Cell Volume

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Blood Volume per kg Body Weight

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Frequently Asked Questions

What formula does this blood volume calculator use?

This calculator uses the Nadler formula, one of the most widely validated methods for estimating total blood volume. For males: BV = (0.3669 × height_m³) + (0.03219 × weight_kg) + 0.6041. For females: BV = (0.3561 × height_m³) + (0.03308 × weight_kg) + 0.1833. The result is in liters.

What is a normal blood volume for adults?

On average, adult men have approximately 4.7–6.0 liters of blood, while adult women typically have 3.5–5.0 liters. Blood volume correlates with body size, so taller or heavier individuals generally have more blood.

What is hematocrit and why does it matter?

Hematocrit (Hct) is the percentage of blood volume occupied by red blood cells. It is used to split total blood volume into plasma volume and RBC (red blood cell) volume. A normal hematocrit is roughly 38–52% for men and 36–48% for women.

How is plasma volume calculated?

Plasma volume is the portion of blood that is not red blood cells. It is calculated as: Plasma Volume = Total Blood Volume × (1 − Hematocrit / 100). Plasma carries nutrients, proteins, hormones, and waste products.

Why is estimating blood volume clinically important?

Knowing a patient's estimated blood volume is critical in surgical planning, trauma management, blood transfusion decisions, and treatment of anemia. It helps clinicians determine safe blood loss thresholds and appropriate transfusion volumes.

Does blood volume change with age or health conditions?

Yes. Blood volume tends to decrease with age, and conditions like heart failure, kidney disease, dehydration, and anemia can alter it significantly. This calculator provides an estimate based on healthy adult norms and should be used as a clinical reference point.

Can I use this calculator for children?

This calculator is designed for adults using the Nadler formula. Pediatric blood volume estimation uses different formulas — for example, neonates have approximately 85 mL/kg and older children around 70–75 mL/kg. Consult a pediatric reference for children.

How accurate is the Nadler formula?

The Nadler formula is widely used and validated in clinical settings, but like all estimation formulas, it has limitations. It does not account for obesity, extreme muscularity, pregnancy, or certain medical conditions. For precise measurement, nuclear medicine techniques such as radiolabeled albumin studies are used.