The calculated distance (air line) between Remseck am Neckar and Karlsruhe is approximately 41 miles respectively 65 kilometers.
By car or train, the actual journey to Karlsruhe is certainly longer, as only the direct route (as the crow flies) between Remseck am Neckar and Karlsruhe has been calculated here.
Air line (approximately)
65 kilometers
35 nautical miles