The reversible coating material nozzle for a spray gun for coating a workpiece with coating material can be installed in a first and a second installation position in a nozzle mount of the spray gun and comprises a nozzle core having a nozzle core opening and a nozzle nipple that is connected to the nozzle core and has a nozzle nipple opening. In addition, a nozzle channel for the coating material is provided and reaches through the nozzle nipple and the nozzle core and connects the nozzle nipple opening to the nozzle core opening. The nozzle nipple has a cylindrical portion, which in the first installation position forms a form fit with the nozzle mount of the spray gun. In addition, a stop is provided. The ratio between the length (L) from the stop to the cylindrical portion and the nozzle diameter (D) lies in the range between 0.75 and 2.00.