The calculated distance (air line) between Luang Prabang and Muang Xay is approximately 56 miles respectively 91 kilometers.
By car or train, the actual journey to Muang Xay is certainly longer, as only the direct route (as the crow flies) between Luang Prabang and Muang Xay has been calculated here.
Air line (approximately)
91 kilometers
49 nautical miles