# Capacitance Formulas

2 Parallel PlatesCoaxial Cylinders
The formulas on this page allow one to calculate the capacitance for certain given geometries. More complex problems typically require one to model the geometry and solve using Finite Element Analysis.

2 Parallel Plane Plates

Diagram of a Parallel Plate Capacitor |
Equation for a Parallel Plate Capacitor |
e is the permittivity (F/m)
e_{0 }is the permittivity of free space (F/m)
e_{r }is the relative permittivity of the dielectric
A is the area of the electrodes (length, l * width, w in m^{2})
d is the distance between the plates (m) |

2 Coaxial Cylinders

Diagram for a Coaxial Cylinder Capacitor |
Equation for a Coaxial Cylinder Capacitor |
e is the permittivity (F/m)
e_{0 }is the permittivity of free space (F/m)
e_{r} is the relative permittivity of the dielectric
a is the radius of the inner cylinder
b is the radius of the outer cylinder
l is the length of the cylinders (m) |

Send consulting inquiries, comments, and suggestions to richard.ness@nessengr.com