The calculated distance (air line) between Tona and Caldes de Montbui is approximately 15 miles respectively 24 kilometers.
By car or train, the actual journey to Caldes de Montbui is certainly longer, as only the direct route (as the crow flies) between Tona and Caldes de Montbui has been calculated here.
Air line (approximately)
24 kilometers
13 nautical miles