Field on Axis of a Ring Magnet

Calculates the field strength on the axis of an axially magnetized ring magnet.

Fill in all of the black-outlined boxes, and the results will appear in the light-gray boxes. Units may be selected as either CGS (Gauss, in.) or SI (mTesla, mm). The required geometrical inputs are defined in the diagram. Negative values of "d" calculate the axial field strength below the top surface of the ring magnet.

This calculation works best with magnetic materials displaying "straight line" demagnetization curves.