The calculated distance (air line) between Savannakhet and Kosum Phisai is approximately 115 miles respectively 184 kilometers.
By car or train, the actual journey to Kosum Phisai is certainly longer, as only the direct route (as the crow flies) between Savannakhet and Kosum Phisai has been calculated here.
Air line (approximately)
184 kilometers
99 nautical miles