A typical 100-watt solar panel is 41. On a 1,000 sq ft roof with 75% usable area, you could theoretically fit 123 of them — but you'd be much better off using a smaller number of bigger panels. Quick answer: A modern residential solar panel measures roughly 66–82 inches long, 40–45 inches wide, and 1. 6 inches thick, weighs 40–55 lb, and produces 350–460 watts. Different factors come into play regarding the dimensions of solar panels, such as the technology used. The 100-watt solar panel represents a common entry point into off-grid power generation for many users.