The calculated distance (air line) between Pul-e ‘Alam and Khōst is approximately 69 miles respectively 111 kilometers.
By car or train, the actual journey to Khōst is certainly longer, as only the direct route (as the crow flies) between Pul-e ‘Alam and Khōst has been calculated here.
Air line (approximately)
111 kilometers
60 nautical miles