ESDU 91038 provides details of a computer program that implements the calculations method of ESDU 89045 and provides a method for predicting the minimum lubricant film thickness in concentrated contacts (Hertzian contacts) that occur@ for example@ in rolling element bearings@ variable speed traction drives and many types of gears. The program may be applied for the contact of metallic@ plastic or ceramic components lubricated by mineral oils and other liquids such as those used in traction drives. In addition to calculation of minimum film thickness@ the program calculates the proportions and orientation of the contact ellipse@ the direction of lubricant entrainment and several non-dimensional quantities of theoretical interest. The program will also@ optionally@ calculate the lamda ratio so that the adequacy of the lubricant film thickness can be assessed.