The calculated distance (air line) between Kuala Lumpur and Kuala Selangor is approximately 33 miles respectively 54 kilometers.
By car or train, the actual journey to Kuala Selangor is certainly longer, as only the direct route (as the crow flies) between Kuala Lumpur and Kuala Selangor has been calculated here.
Air line (approximately)
54 kilometers
29 nautical miles