The calculated distance (air line) between Yerevan and Doğubayazıt is approximately 49 miles respectively 79 kilometers.
By car or train, the actual journey to Doğubayazıt is certainly longer, as only the direct route (as the crow flies) between Yerevan and Doğubayazıt has been calculated here.
Air line (approximately)
79 kilometers
43 nautical miles