The calculated distance (air line) between Calderara di Reno and Castel San Pietro Terme is approximately 19 miles respectively 31 kilometers.
By car or train, the actual journey to Castel San Pietro Terme is certainly longer, as only the direct route (as the crow flies) between Calderara di Reno and Castel San Pietro Terme has been calculated here.
Air line (approximately)
31 kilometers
17 nautical miles