The calculated distance (air line) between Ban Houayxay and Luang Prabang is approximately 116 miles respectively 186 kilometers.
By car or train, the actual journey to Luang Prabang is certainly longer, as only the direct route (as the crow flies) between Ban Houayxay and Luang Prabang has been calculated here.
Air line (approximately)
186 kilometers
100 nautical miles