Nowadays, the use of IoT devices is essential in most sectors along with a rising concern regarding their energy consumption. Therefore, an accurate estimation of the energy consumption of such devices is required for energy-efficient improvements. This paper presents Energy Measurement Model (EMM), an energy estimation tool for Raspberry Pi 3 Model B+. It is a software-based model used to estimate the local energy consumption of a device by taking into consideration CPU utilization. The error rate of our model averages at 1.25%. Using this model, we study the energy impact of a set of algorithms, programming languages and compilers.