The calculated distance (air line) between Áyios Konstandínos and Chalkída is approximately 120 miles respectively 193 kilometers.
By car or train, the actual journey to Chalkída is certainly longer, as only the direct route (as the crow flies) between Áyios Konstandínos and Chalkída has been calculated here.
Air line (approximately)
193 kilometers
104 nautical miles