A method for estimating the burning rate of solid propellant from rocket motor firings is described. By use of this method the burning rate's variation with pressure can be determined in every single firing as opposed to commonly used methodology where average burning rate is estimated at mean pressure for a number of firings in order to give pressure variation. The method is applied to five firings of rocket motors with charges of a standard propellant. The result are compared with strand burning tests and the burnt distance divided by burning time estimate and some of the benefits and limitations of the method are identified.