The calculated distance (air line) between Nakhon Pathom and Lop Buri is approximately 79 miles respectively 127 kilometers.
By car or train, the actual journey to Lop Buri is certainly longer, as only the direct route (as the crow flies) between Nakhon Pathom and Lop Buri has been calculated here.
Air line (approximately)
127 kilometers
69 nautical miles