ESDU 75026 gives for a wide range of geometries curves for static pressure recovery for diffusers (with or without tailpipes) having a parallel core, having a core diverging at 5 degrees and having a core converging at an angle equal to the divergence angle of the walls. The geometric parameters taken into account are area ratio, diffuser length to annular gap ratio, and divergence angle. Curves for geometries for maximum pressure recovery are included in all cases for diffusers of given length and of given area ratio. An equation is given that enables the total pressure loss to be calculated from the static pressure recovery data for diffusers without tailpipes and a modification is suggested for diffusers with tailpipes. Various other factors that affect performance are discussed. The curves are based on data from a wide range of experimental sources.