The calculated distance (air line) between Bad Sooden-Allendorf and Karlsruhe is approximately 171 miles respectively 275 kilometers.
By car or train, the actual journey to Karlsruhe is certainly longer, as only the direct route (as the crow flies) between Bad Sooden-Allendorf and Karlsruhe has been calculated here.
Air line (approximately)
275 kilometers
149 nautical miles