Estimates the mass and volume of blood from body weight and blood specific gravity.
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Calculation basis and official references
Reviewed on:
This calculator is not a diagnosis, treatment plan, or prescription. Please consult a qualified clinician about your medical decisions.
Formula basis
Blood mass (kg) = body weight (kg) / 13. Blood volume (mL) = blood mass (kg) / specific gravity x 1000 (derived from the relationship specific gravity = mass / volume, solved for volume).
Calculation method
Estimates the mass of blood (using the common rule of thumb that blood makes up about 1/13 of body weight) and, from the entered blood specific gravity, the corresponding blood volume.
Exclusions and checks required
The 1/13 ratio is a general adult approximation; actual blood volume varies with body composition (muscle mass, fat mass, etc.).
Blood specific gravity is a user-entered approximate value; the actual specific gravity varies by individual health status and testing conditions.
This is only an estimate and is not a substitute for an actual medical measurement of circulating blood volume (e.g., dye-dilution methods).
Example input:：Body weight 65kg, blood specific gravity 1.055
weight
65
density
1.055
Both the mass and volume are estimates based on body weight and vary between individuals.
Estimates the mass and volume of blood from body weight and blood specific gravity.
What values should I enter?
Applies to: Blood pressure & blood
How should I interpret this estimate?
Estimates the mass of blood (using the common rule of thumb that blood makes up about 1/13 of body weight) and, from the entered blood specific gravity, the corresponding blood volume.
How to use
Enter your input values and press Calculate.
Review the result and compare it with expected context.
Blood mass (kg) = body weight (kg) / 13. Blood volume (mL) = blood mass (kg) / specific gravity x 1000 (derived from the relationship specific gravity = mass / volume, solved for volume).