# Capsule (geometry)

A capsule, also known as a stadium of revolution, is a basic three dimensional geometric shape. It consists of a cylinder with hemispherical ends.[1] Another name for this shape is "spherocylinder".[2] The shape is used for containers for pressurised gasses.

## Formulas

The volume of a capsule is calculated by the formula ${\displaystyle \pi r^{2}\left({\frac {4}{3}}r+a\right)}$ where ${\displaystyle r}$ is the radius of the cylinder and hemispheres and ${\displaystyle a}$ is the length of the cylindrical part.

The surface area formula is ${\displaystyle 2\pi r(2r+a)}$ where ${\displaystyle r}$ is the radius of the cylinder and hemispheres and ${\displaystyle a}$ is the length of the cylindrical part.[3]

## References

1. Template:Cite web
2. {{#invoke:Citation/CS1|citation |CitationClass=journal }}
3. Template:Cite web