The use of combustion engines in portable applications has several applications, such as: high-pressure washers, motogenerators, crushers and pumping. However, the autonomy of such equipment does not always follow its advancement in efficiency and robustness. Therefore, the monitoring of the fuel level of these machines is necessary to know about their autonomy. This article refers to the development of a portable capacitive transducer for fuel level measurement, consisting of a plug-in device, easy to install and compact. From its construction and configuration, the device produces a frequency signal inversely proportional to the capacitance variation of the sensor element. The transducer technique is non-invasive and it takes advantage of the tank shell characteristic construction for coupling of the device.