The calculated distance (air line) between Saarbrücken and Bad Kreuznach is approximately 57 miles respectively 92 kilometers.
By car or train, the actual journey to Bad Kreuznach is certainly longer, as only the direct route (as the crow flies) between Saarbrücken and Bad Kreuznach has been calculated here.
Air line (approximately)
92 kilometers
49 nautical miles