The calculated distance (air line) between Grenzach-Wyhlen and Karlsruhe is approximately 106 miles respectively 171 kilometers.
By car or train, the actual journey to Karlsruhe is certainly longer, as only the direct route (as the crow flies) between Grenzach-Wyhlen and Karlsruhe has been calculated here.
Air line (approximately)
171 kilometers
92 nautical miles