The calculated distance (air line) between Louvain-la-Neuve and Uccle is approximately 15 miles respectively 24 kilometers.
By car or train, the actual journey to Uccle is certainly longer, as only the direct route (as the crow flies) between Louvain-la-Neuve and Uccle has been calculated here.
Air line (approximately)
24 kilometers
13 nautical miles