Permeability is the ability with which the magnetic material forces the magnetic flux through a given medium. Permeability is the magnetic property of the medium.

The flow of flux in a magnetic material is depend on both magnetic field strength and magnetic property or medium of the magnetic material.

There are two types of permeability.

1) absolute permeability

2) relative permeability

**1) absolute permeability:** absolute permeability is the ratio of magnetic flux density (B) to magnetic field strength (H) in a particular medium is called as absolute permeability.

Mathematically absolute permeability is given by,

μ=B/H

Where, B is magnetic flux density.

H is magnetic field strength or magnetizing force.

μ is absolute permeability.

The unit of absolute permeability is heneries per metre (H/m)

**2) relative permeability: **relative permeability is the ratio of magnetic flux density (B) in a medium to magnetic flux density in free space (B_{0}).

Mathematical relative permeability is given by,

μ_{r}=B/B_{0}

The magnetic field strength (H) is same for both. Relative permeability is unitless it has no dimensions.