The calculated distance (air line) between Leverkusen and Wahn-Heide is approximately 13 miles respectively 21 kilometers.
By car or train, the actual journey to Wahn-Heide is certainly longer, as only the direct route (as the crow flies) between Leverkusen and Wahn-Heide has been calculated here.
Air line (approximately)
21 kilometers
11 nautical miles