The calculated distance (air line) between Néa Kallikráteia and Thessaloníki is approximately 24 miles respectively 38 kilometers.
By car or train, the actual journey to Thessaloníki is certainly longer, as only the direct route (as the crow flies) between Néa Kallikráteia and Thessaloníki has been calculated here.
Air line (approximately)
38 kilometers
21 nautical miles