Tank Volume Calculator
This tank volume calculator finds the total capacity and filled volume of cylinder, rectangle and capsule tanks in gallons, liters, cubic meters and more.
Calculate Tank Volume
Results
| Unit | Total Capacity | Filled Volume |
|---|
Methods to calculate tank volume
Methods to calculate tank volume depend on the shape of the tank, with cylinders, rectangles and capsules each using a different formula for total capacity and filled volume.
Horizontal cylinder tank volume
A horizontal cylinder tank has its total volume calculated as pi times the radius squared times the length. The filled volume uses the circular segment method, which calculates the wetted cross sectional area at the given fill depth and multiplies it by the tank length.
Vertical cylinder tank volume
A vertical cylinder tank has its total volume calculated as pi times the radius squared times the height. The filled volume simply substitutes the fill depth for the height, since a partially filled vertical cylinder is just a shorter cylinder with the same radius.
Rectangle tank volume
A rectangle tank has its total volume calculated as length times width times height. The filled volume uses the same formula but substitutes the fill depth for the height, since a partially filled rectangular tank is simply a shorter rectangular prism.
Capsule tank volume
A capsule tank is treated as a cylinder with two hemispherical ends, so its total volume combines the cylinder volume formula with the sphere volume formula. Filled volume calculations use the circular segment method for the cylindrical section and the spherical cap method for the rounded ends.
Formulas for tank capacity and fill volume
Formulas for tank capacity and fill volume below summarize the calculations used for each tank type supported by this calculator.
Horizontal Cylinder
V(tank) = πr²l
V(fill) uses circular segment area × l
Vertical Cylinder
V(tank) = πr²h
V(fill) = πr²f
Rectangle
V(tank) = lwh
V(fill) = lwf
Capsule
V(tank) = πr²((4/3)r + a)
V(fill) uses segment plus spherical cap
Unit conversions used in tank volume results
Unit conversions used in tank volume results allow the same calculation to be displayed in US gallons, Imperial gallons, liters, cubic meters and cubic feet for convenience.
Converting cubic feet to gallons
One cubic foot equals approximately 7.48052 US gallons or 6.22884 Imperial gallons. This conversion factor allows a volume calculated in cubic feet to be expressed as a liquid capacity in gallons.
Converting cubic meters to liters
One cubic meter equals exactly 1000 liters, since a liter is defined as one thousandth of a cubic meter. This makes converting between cubic meters and liters a simple matter of moving the decimal point.
Frequently asked questions
The total volume of a horizontal cylinder tank equals pi times the radius squared times the length. The radius is half the diameter, and the result represents the full capacity of the tank when completely filled.
The total volume of a vertical cylinder tank equals pi times the radius squared times the height. The filled volume uses the same formula but replaces the height with the fill depth.
The filled volume of a horizontal cylinder tank is found using the circular segment method, which calculates the area of the wetted cross section based on the fill depth and multiplies it by the tank length. If the fill depth is more than half the diameter, the empty segment is subtracted from the total volume instead.
There are approximately 7.48052 US gallons in one cubic foot. This conversion factor is used to convert tank volumes calculated in cubic feet into gallon measurements.
A US gallon equals approximately 3.78541 liters, while an Imperial gallon equals approximately 4.54609 liters, making the Imperial gallon about 20 percent larger. The United States uses US gallons, while the United Kingdom and some other countries use Imperial gallons.
Tank volume calculations assume perfect geometric shapes and inside dimensions, so they provide close estimates rather than exact figures for real tanks. Actual tanks may have wall thickness, fittings, or rounded edges that cause the true capacity to differ slightly from the calculated value.