sysLoss is a tool for analyzing power trees in systems, boards and circuits - from the smallest IoT sensor to large industrial installations. The tool is efficient and easy to use, the analysis result provides a detailed report on voltages, currents, power, loss and efficiency for every component defined in the system. sysLoss can interface to external battery models to estimate battery life. Output format is Pandas DataFrame: Create charts, plots and export to Excel and other formats. sysLoss can also produce graphical power tree diagrams in a wide range of image formats.