A method of using fast scan NMR spectroscopy to determine the magnetic field gradient (B gradient) for magnetic flux densities (B field) (0.08<or=B<or=2 T) is described in which it is not necessary to either move the NMR probe or modulate the magnetic field. The B field and the B gradient can be both measured and monitored simultaneously using the same instrumentation. This instrumentation is extremely simple since a marginal oscillator is used as a low power, swept frequency RF source. It is shown that B gradients can be measured from less than 0.03 to 8 mT m^-1 with a resolution of 0.003 mT m^-1. However, only relative and not absolute B gradient values can be determined without calibration and the calibration is nonlinear. It is shown that this method can be used to distinguish between linear and nonlinear B gradients.