The calculated distance (air line) between Samdrup Jongkhar and Sarpang is approximately 76 miles respectively 123 kilometers.
By car or train, the actual journey to Sarpang is certainly longer, as only the direct route (as the crow flies) between Samdrup Jongkhar and Sarpang has been calculated here.
Air line (approximately)
123 kilometers
66 nautical miles