By using the program MATLAB and the package CoolProp in iterative calculations and optimization the best solution of the heat exchanger for the given initial conditions is obtained. In merging of various sources and adding new ones functions are made for the calculation of heat exchanger characteristics. The beginning of the paper deals with the geometry and configuration of the heat exchanger. After obtaining the dimensions and areas the pressure drops, total heat transfer coefficient and the correction factor can be calculated. By determining all of the necessary values the predicted area i.e. length for the heat exchange can be calculated. The second part of the paper deals with fluid flows through the shell and tubes where the characteristics of the fluid after each row of tubes can be calculated. A more detailed passage through the heat exchanger gives more realistic values than the predicted ones. When all the values of the heat exchanger are obtained, the cost of manufacturing is reached which is one of the most important factors and the main value in terms of optimization. At the end of the paper a unified main function is used for the optimization in 3 different ways of which the most important is through multi-objective genetic optimization that is part of the MATLAB program.