The calculation is developed for geometrical designs of belt and chain transmissions with more sprocket wheels (max. 15). It solve the necessary length of the belt (chain) using known positions and diameters of sprocket wheels. Application is developed in MS Excel, is multi-language, supports Imperial and Metric units and support many 2D CAD systems. (AutoCAD, AutoCAD LT, IntelliCAD, TurboCAD...).