# How do you calculate gallons in a round tank?

###### April 11, 2013 12:39AM

All answers presume measurements are in Decimal form of feet (i.e. 1.5 feet, rather than 1 foot 6 inches or 0.5 yards)

If the tank is cylindrical (generally what people refer to as a "rounded" tank), then here is the formula:

diameter of the circular end * PI (3.14159...) * Length of the tank * 7.48052 (gallons per cubic feet)

If you are talking about a spherical tank, then here is the measurement:

Radius of the sphere, cubed * PI * 7.48052 * 4 / 3

if you know the Diameter of the sphere, the radius is one half this.

If you know the circumference of the sphere, the radius is one half this, then further divided by PI.

If the tank is a "squashed cylinder" (i.e. a cylinder where one end axis is longer than the other) - in other words, a cylinder with an eliptical cross-section, then the measurement is:

Length of the tank * length of the long axis of the elipse end * length of the short axis of the elipse end * PI * 7.48052