The calculated distance (air line) between Mont-Saint-Guibert and Etterbeek is approximately 17 miles respectively 27 kilometers.
By car or train, the actual journey to Etterbeek is certainly longer, as only the direct route (as the crow flies) between Mont-Saint-Guibert and Etterbeek has been calculated here.
Air line (approximately)
27 kilometers
15 nautical miles