The calculated distance (air line) between Serchhīp and Kailāshahar is approximately 89 miles respectively 144 kilometers.
By car or train, the actual journey to Kailāshahar is certainly longer, as only the direct route (as the crow flies) between Serchhīp and Kailāshahar has been calculated here.
Air line (approximately)
144 kilometers
78 nautical miles