Box culverts are the monolithic unit build to pass across railway lines, roadways, etc. earthworks are made to balance the discharge water on both sides. Box takes different types of loads created by a cushion, traffic, water, soil, etc. This paper deals with the optimum design of box culvert by using Newton's-Raphson Method and AppDesigner in MATLAB Software R2017a and studies the design parameters such as the influence of depth of earth fill at the top slab of the culvert, earth pressure, factor Dead Load, Live load, effective width, etc. In this paper, the study of the box-culvert with normal and minimum cushion analyzed for different classes of loadings and conclusions made on the basis of Newton's-Raphson Method normal and minimum cushion and normal cushioning cases.