A heat exchanger is a device designed to efficiently transfer heat between two process fluids, are used in industrial and household processes. In this project, we developed a double-pipe heat exchanger with a multi-pass parallel flow configuration. The inner pipe is constructed from copper, while the outer pipe is made of mild steel. Both fluids used in the heat exchange process are water, and their flow rates are selected to ensure cost-effectiveness. To assess the heat exchanger's performance and pressure drop, we employed the Log Mean Temperature Difference (LMTD) method. We utilized SolidWorks software for the project's design phase and HTRI software to determine the optimal design configuration. The necessary correlations for calculating the Nusselt number and other relevant data are taken from reference books.