The cylindrical coordinate system is similar to that of the spherical coordinate system, but is an alternate extension to the polar coordinate system. Its elements, however, are something of a cross between the polar and Cartesian coordinates systems.

Cylindrical coordinates

The coordinate system uses the standard polar coordinate system in the x-y plane, utilizing a distance from the origin (r) and an angle (θ) of extension from the positive x-axis (or pole). However, the third coordinate is a simple z-axis distance from above the x-y plane, just as any standard Cartesian system would utilize.

The coordinate (r, \theta, h) represents the coordinate that exists at height h above the x-y plane (the z-coordinate). While, looking down from above, onto the x-y plane, the coordinate would appear to be at the polar coordinate (r, θ)


Given the coordinates:

Spherical: (\rho, \phi, \theta)
Cylindrical: (r, \theta, h)
Cartesian: (x, y, z)

Spherical coordinates may be converted to cylindrical coordinates by:

 r = \rho \sin \phi \,
 \theta  = \theta \,
 h  = \rho \cos \phi \,

Cylindrical coordinates may be converted to spherical coordinates by:

{\theta}=\theta \quad

Cartesian coordinates may be converted into cylindrical by:

r = \sqrt{x^2 + y^2}
\theta = \arctan(\frac{y}{x})
h = z

Cylindrical coordinates may be converted into Cartesian by:

x = r \cos \theta
y = r \sin \theta
z = h