The calculated distance (air line) between Düsseldorf and Porz am Rhein is approximately 26 miles respectively 42 kilometers.
By car or train, the actual journey to Porz am Rhein is certainly longer, as only the direct route (as the crow flies) between Düsseldorf and Porz am Rhein has been calculated here.
Air line (approximately)
42 kilometers
23 nautical miles