ESDU 91037 provides details of a computer program that implements the calculations method of ESDU 85027 and provides a method for predicting the minimum lubricant film thickness in concentrated contacts (Hertzian contacts) that occur@ for example@ in rolling element bearings and many types of gears. The program may be applied for an almost limitless range of solid/lubricant combinations including metals@ polymers or rubbers with mineral oils or water lubricants. The program strictly applies to nominal line contacts but some point contacts may also be analysed. In addition to the calculation of minimum film thickness the program will also@ optionally@ calculate the lamda ratio so that the adequacy of the lubricant film thickness can be assessed.