The calculated distance (air line) between Büyükçekmece and Eminönü is approximately 20 miles respectively 32 kilometers.
By car or train, the actual journey to Eminönü is certainly longer, as only the direct route (as the crow flies) between Büyükçekmece and Eminönü has been calculated here.
Air line (approximately)
32 kilometers
17 nautical miles