The calculated distance (air line) between Ogulin and Kostanjevica na Krki is approximately 41 miles respectively 66 kilometers.
By car or train, the actual journey to Kostanjevica na Krki is certainly longer, as only the direct route (as the crow flies) between Ogulin and Kostanjevica na Krki has been calculated here.
Air line (approximately)
66 kilometers
36 nautical miles