Bluetooth is considered as a low-cost short-range wireless technology to provide communication functionalities, ranging from wire replacement to simple personal area network. In Bluetooth local networking applications a critical issue still under study is the evaluation of the network capacity when multiple piconets are simultaneously active in the same area, while providing mutual interference. In this paper we first provide a review of the main characteristics of the Bluetooth technology then we propose a semi-analytical approach to calculate the packet loss probability, and the aggregate network throughput. The analytical approach was validated by extensive comparison with simulation results showing a good agreement.