Parametric analysis is often used for exploring design options and identifying the relationship between design parameters and performance. The jEPlus tool has been developed specifically for performing complex parametric analysis with EnergyPlus. It provides a GUI for defining design parameters, editing models, manage simulation runs, and collecting results. With the GUI, hundreds of thousands of simulation cases may be created in the matter of minutes. The tool is written in Java, as an open source project. It works with all existing and the future EnergyPlus versions on Windows, Mac and Linux platforms. The main features of jEPlus include: – Complete GUI providing controls needed for setting and managing parametric projects – Creating portable projects that can be moved between computers or executed online – Supporting all EnergyPlus versions, including future releases – Flexible syntax of specifying parameter values, including user-defined combinations, distribution sampling, and inline calculations – Managing simulations in parallel to take full advantage of the modern computer hardware – Simulation results being collected from various E+ output files into the CSV format – Python scripts and user-defined formulae can be used in post-processing results – Command-line interface for employing jEPlus as a simulation manager in other programs/tools