Wide bang gap devices, especially GaN devices are promising in the improvement of power density of the converter due to their fast switching speed and their smaller package. The paper presents how the layout change will affect the power density of an isolated dc-dc converter. In this paper, two layout has been analyzed and presented for paralleling of four GaN FETs. Experimental results from the converters with two different layout are presented in this paper. The power rating of the converter has increased from 2 kW to 2.6 kW converter by the optimization of layout. The measured efficiency curve of both the converter is shown in this paper. The maximum measured efficiency of the converter is 98.5% for the 2 kW converter and 98.8% for the 2.6 kW converter. The power density of the converter has increased by 30% with the optimization of the layout.