The calculated distance (air line) between Prato and Sesto Fiorentino is approximately 6 miles respectively 10 kilometers.
By car or train, the actual journey to Sesto Fiorentino is certainly longer, as only the direct route (as the crow flies) between Prato and Sesto Fiorentino has been calculated here.
Air line (approximately)
10 kilometers
5 nautical miles