The calculated distance (air line) between Bet Shemesh and Modiin Ilit is approximately 14 miles respectively 23 kilometers.
By car or train, the actual journey to Modiin Ilit is certainly longer, as only the direct route (as the crow flies) between Bet Shemesh and Modiin Ilit has been calculated here.
Air line (approximately)
23 kilometers
12 nautical miles