The calculated distance (air line) between Sri Jayewardenepura Kotte and Katunayaka is approximately 20 miles respectively 32 kilometers.
By car or train, the actual journey to Katunayaka is certainly longer, as only the direct route (as the crow flies) between Sri Jayewardenepura Kotte and Katunayaka has been calculated here.
Air line (approximately)
32 kilometers
17 nautical miles