The calculated distance (air line) between Formello and Bagni di Tivoli is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Bagni di Tivoli is certainly longer, as only the direct route (as the crow flies) between Formello and Bagni di Tivoli has been calculated here.
Air line (approximately)
29 kilometers
16 nautical miles