Estimate body volume from your weight using an average human density of 1.01 kg/L, body fat %, or a measured density, in liters, gallons and cubic feet.
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Body Volume Formula
Body volume is weight divided by body density. The density can be the average 1.01 kg/L, a measured value, or an estimate from body fat percentage.
Density from body fat percentage (Siri):
Body volume:
- V = body volume in liters
- W = body weight in kilograms
- D = body density in kg/L
- BF = body fat percentage
By default, the calculator divides weight by an average density of 1.01 kg/L. With Custom density, it divides weight directly by the value you enter from a hydrostatic weighing test, BOD POD report, or similar measurement. Results are shown in liters with equivalents in US gallons, cubic meters, and cubic inches.
Typical Values and Conversions
Body density for healthy adults usually falls between about 1.02 and 1.10 kg/L. Higher lean mass pushes density up; higher fat mass pulls it down toward water (1.00 kg/L). Volume in liters is close to weight in kilograms because the body is mostly water.
| Body composition | Approx. density (kg/L) | Volume per 70 kg |
|---|---|---|
| Very lean / athletic | 1.080 – 1.100 | 63.6 – 64.8 L |
| Average adult | 1.040 – 1.070 | 65.4 – 67.3 L |
| Higher body fat | 1.000 – 1.030 | 68.0 – 70.0 L |
| Pure water reference | 1.000 | 70.0 L |
| From | To | Multiply by |
|---|---|---|
| Liters | US gallons | 0.26417 |
| Liters | Cubic meters | 0.001 |
| Liters | Cubic inches | 61.024 |
| Liters | Cubic feet | 0.03531 |
Example Problem
65 kg, 28% body fat.
Density = 495 ÷ (28 + 450) = 1.0356 kg/L. Volume = 65 ÷ 1.0356 = 62.8 L, or about 16.6 US gallons.
Male, 80 kg, measured density 1.062 kg/L.
Volume = 80 ÷ 1.062 = 75.3 L, or about 19.9 US gallons.
FAQ
Why is body volume close to body weight? Because the body's density sits near 1 kg/L. A 70 kg person occupies roughly 65 to 70 liters.
Which mode is more accurate? The density mode, if your density value comes from underwater weighing, air displacement plethysmography (BOD POD), or DXA-derived data. The average-density and body-fat options are estimates only.
Does this give body fat percentage? Mainly volume. The body density option also shows a Siri body fat estimate from the density.
Why did I get a warning about density? The result fell outside the typical 0.98 to 1.12 kg/L range. Check that you used the correct unit and that weight and volume were entered correctly.
