The calculated distance (air line) between Sri Jayewardenepura Kotte and Ratnapura is approximately 37 miles respectively 59 kilometers.
By car or train, the actual journey to Ratnapura is certainly longer, as only the direct route (as the crow flies) between Sri Jayewardenepura Kotte and Ratnapura has been calculated here.
Air line (approximately)
59 kilometers
32 nautical miles