How do you calculate the magnetic dipole moment of a bar magnet?

The strength of a magnet can be determined by measuring its flux density (B) which is expressed in teslas. The flux density will vary according to where relative to the magnet it is being measured. The instrument for doing this is a flux-density meter (which was called a 'gaussmeter' - 'gauss' being an obsolete unit of measurement for flux density, from the cgsA metric system).