[en] A method is described for rapid and accurate computation of diagnostic x-ray spectra. Accuracy limitations of Kramer's equation are overcome by providing intensity correction factors derived from published measured data. Use of a parameter based on the energy of the Kramers spectrum intensity peak permits deriving master factor curves which are remarkably independent of kVp, waveform and filtration. Computed and measured spectra generally agree to better than +- 1 keV for beams generated at 100 kVp and below. Possible application of the method to higher energy diagnostic beams is discussed