The flame jet width and flame jet velocity of the burnt gases of a premixedBunsen-type flame are important parameters to quantify the heat transfer rate ofthese flames.In this paper a simple expression is derived to estimate the resulting flame jetwidth and flame jet velocity of burnt gases of a free flame afterexpansion over the flame front for the special case of plug flow in and abovethe burner. The results of PIV experiments on three different flame types,having different oxygen concentrations, are presented. The model is validatedwith these measurements and shows good agreement. Deviations occur, however,when the curved flame front area of the flame tip is not negligible compared tothe total flame area.