The calculated distance (air line) between Modi‘in Makkabbim Re‘ut and Kiryat Gat is approximately 25 miles respectively 39 kilometers.
By car or train, the actual journey to Kiryat Gat is certainly longer, as only the direct route (as the crow flies) between Modi‘in Makkabbim Re‘ut and Kiryat Gat has been calculated here.
Air line (approximately)
39 kilometers
21 nautical miles