The calculated distance (air line) between Buchholz in der Nordheide and Duisburg is approximately 185 miles respectively 298 kilometers.
By car or train, the actual journey to Duisburg is certainly longer, as only the direct route (as the crow flies) between Buchholz in der Nordheide and Duisburg has been calculated here.
Air line (approximately)
298 kilometers
161 nautical miles