The calculated distance (air line) between Dießen am Ammersee and Karlsruhe is approximately 144 miles respectively 231 kilometers.
By car or train, the actual journey to Karlsruhe is certainly longer, as only the direct route (as the crow flies) between Dießen am Ammersee and Karlsruhe has been calculated here.
Air line (approximately)
231 kilometers
125 nautical miles