The calculated distance (air line) between Modiin Ilit and Kiryat Gat is approximately 28 miles respectively 45 kilometers.
By car or train, the actual journey to Kiryat Gat is certainly longer, as only the direct route (as the crow flies) between Modiin Ilit and Kiryat Gat has been calculated here.
Air line (approximately)
45 kilometers
24 nautical miles