The calculated distance (air line) between Ban Muang-Nan and Luang Prabang is approximately 33 miles respectively 52 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 Muang-Nan and Luang Prabang has been calculated here.
Air line (approximately)
52 kilometers
28 nautical miles