Bladder Volume Calculator

What Is Bladder Volume on Ultrasound?

Bladder volume from ultrasound uses three perpendicular dimensions and a shape coefficient to estimate how much urine the bladder holds. Clinicians use this for urinary retention, post-void residual, and pediatric bladder assessment. Related tools: Baby Milk Intake Calculator and Adjusted Body Weight Calculator.

Bladder Volume Formula

$$\mathrm{Volume} = \mathrm{width} \times \mathrm{height} \times \mathrm{length} \times k$$

Dimensions are in centimeters. The coefficient $k$ depends on bladder shape: ellipsoid (0.81), cuboid (0.89), triangular (0.66), prolate (0.52), or unknown (0.77). The result is in milliliters.

Shape Coefficients

Ellipsoid is common for a normally distended bladder. Cuboid suits a more rectangular outline. Triangular and prolate coefficients apply when the bladder contour matches those geometries. Use custom when you have a validated local coefficient.