The calculated distance (air line) between Gebze and Merter Keresteciler is approximately 32 miles respectively 51 kilometers.
By car or train, the actual journey to Merter Keresteciler is certainly longer, as only the direct route (as the crow flies) between Gebze and Merter Keresteciler has been calculated here.
Air line (approximately)
51 kilometers
28 nautical miles