A dynamic background subtraction circuit is disclosed which improves the display resolution of radiation energy spectra, such as X-ray energy spectra in an X-ray energy spectrometer. In this circuit, the number of radiation events (counts) occurring at a reference or background energy level is subtracted from the number of radiation events (counts) occurring at a second energy level under study. The output of this circuit is a real-time (dynamic) approximation of the count rate at the energy level under study, but with resolution improved by subtraction of the background counts.