The calculated distance (air line) between Buchholz in der Nordheide and Bochum is approximately 170 miles respectively 273 kilometers.
By car or train, the actual journey to Bochum is certainly longer, as only the direct route (as the crow flies) between Buchholz in der Nordheide and Bochum has been calculated here.
Air line (approximately)
273 kilometers
147 nautical miles