The calculated distance (air line) between Sandwīp and Uttar Char Fasson is approximately 51 miles respectively 83 kilometers.
By car or train, the actual journey to Uttar Char Fasson is certainly longer, as only the direct route (as the crow flies) between Sandwīp and Uttar Char Fasson has been calculated here.
Air line (approximately)
83 kilometers
45 nautical miles