An equivalent‐tone method for calculating the loudness of sounds is described. With this method the spectrum of the sound is divided into frequency bands which are treated as pure tones in determining their loudness. The individual values of loudness are added to obtain the total loudness of the sound. Calculations for bands of white noise and for complex tones are compared with subjectively obtained data of Pollack and Fletcher and Munson. The agreement between calculated and experimental values is good. It is felt that improvement of the method must await further psychoacoustic data.