The calculated distance (air line) between Ḩayy al Bunayyāt and As Salţ is approximately 14 miles respectively 22 kilometers.
By car or train, the actual journey to As Salţ is certainly longer, as only the direct route (as the crow flies) between Ḩayy al Bunayyāt and As Salţ has been calculated here.
Air line (approximately)
22 kilometers
12 nautical miles