The calculated distance (air line) between Fatehpur Chaurāsi and Lucknow is approximately 41 miles respectively 66 kilometers.
By car or train, the actual journey to Lucknow is certainly longer, as only the direct route (as the crow flies) between Fatehpur Chaurāsi and Lucknow has been calculated here.
Air line (approximately)
66 kilometers
35 nautical miles