A comparison of spray angle measurements obtained using optical and mechanical methods is presented. The optical method used extinction tomography at two axial locations for obtaining surface area density contours. These surface area density contours were used to define the spray angle. The method is similar to that proposed by the Society of Automotive Engineers for defining spray angles from gasoline direct injection (GDI) injectors. The mechanical method used a protractor to directly measure angles from front-illuminated sprays. Three types of fuel atomizers were used to obtain spray angles. The results obtained are analyzed to provide a consistent approach to spray angle measurements using extinction.