EnergyBox is a parametrised estimation tool that uses packet traces as input to simulate the energy consumption of communication in mobile devices. This tool models the transmission behaviour of a smart phone by analysing a recorded packet trace from the device. The purpose of the thesis is to reimplement the original EnergyBox energy consumption modelling tool. The project aims to develop support for a graphical user interface (GUI) and a code base that is easier to modify and maintain. The motivation for the reimplementation of the tool is to simplify its usage and to structure the code so that new features can be added. The existing features such as the calculation of total power consumed by the packet trace and the modelling of a device's energy states are reimplemented and new features are developed. Among the new features, a GUI is added to simplify the usage of the application features such as the detection of the recording device's IP address and the ability to alter the configuration parameters used as input to the energy model. The application is written with a GUI and modularity in mind. This is achieved using Java's proprietary new GUI framework - JavaFX, which supports built-in chart and graph GUI elements, that can be easily integrated and supported. The energy modelling engines follow the semantics of the original implementation and the evaluation shows that the new implementation's results are identical to the original tool in 94.94% of the tested cases.