The time varying magnetic flux density in an electrodeless high frequency discharge was measured with a bare wire B-dot probe immersed in plasma. Based on B-dot measurements, the spatial distribution of the current density was determined and integrated over the cross section of the discharge to determine the total discharge current. The total current determined from B-dot measurements was compared with total current measured externally with a current transformer. Agreement between the two methods was very good over a wide range of gas pressures and discharge currents. This work validates that a small, immersed B-dot probe does not significantly perturb the discharge current and can accurately determine current density in a low-pressure gas discharge.