The calculated distance (air line) between Düsseldorf-Pempelfort and Langenfeld is approximately 11 miles respectively 18 kilometers.
By car or train, the actual journey to Langenfeld is certainly longer, as only the direct route (as the crow flies) between Düsseldorf-Pempelfort and Langenfeld has been calculated here.
Air line (approximately)
18 kilometers
10 nautical miles