Permeability of free space

The permeability of free space, μ0, is a physical constant used often in electromagnetism. It is taken to have the exact value of 4π x 10-7 N/A2 (newtons per ampere squared).[1] It is connected to the energy stored in a magnetic field, see Hyperphysics for specific equations.

It is related to the speed of light by the equation


Visit Hyperphysics for more information on this constant.


  1. Hyperphysics. (August 28, 2015). Electric field [Online], Available:

Authors and Editors

Jordan Hanania, Kailyn Stenhouse, Jason Donev