The transformer is the most efficient of transmission and distribution system, with efficiencies typically in the high 90s, it is possible to reduce transformer costs and losses by using round and rectangular conductor winding. This journal presents the result of the difference between round conductor winding and rectangular conductor winding of distribution transformer. The most substation transformers are utilized either circular or rectangular in core and coil assembly. The transformers manufacturing industry improve transformer efficiency and reliability. This paper intended to prove the product would have improved outcomes, a higher standard and sustainability by adapting the product development to the road condition of the country of manufacture. In design consideration, selection of magnetic frame, choice of conductor size, choices of current density are considered.