Quick answer: A modern residential solar panel measures roughly 66–82 inches long, 40–45 inches wide, and 1. In the design and installation of photovoltaic systems, calculating rooftop solar panel dimensions is a critical factor that determines the success of a project. With limited roof space, inaccurate measurement and planning may result in insufficient installed capacity, wasted space, and an extended. Most of the solar modules in the residential category have 60-cell solar panels. These panels come in a standard size, which is approximately 1650 x 990 mm (65 x 39 inches). 6 inches thick, weighs 40–55 lb, and produces 350–460 watts. The full size-by-wattage. In recent years, the mainstream power classes in the European rooftop PV market have stabilised around 430W, 550W and 600W.