In this paper, the design of flat belt has been described and necessary computer program have been developed. The method of determining basic design parameters for flat belt design are belt thickness, width, pulley diameter, initial tension, stress, ratio of tight and slacks side forces, coefficient of friction has been presented by a flow chart and a software tool has been developed by using Visual Basic language. The main objective of developing this software tool is that computer generated outputs have better accuracy than conventional calculation procedure.