The calculated distance (air line) between Teplice and Roudnice nad Labem is approximately 24 miles respectively 39 kilometers.
By car or train, the actual journey to Roudnice nad Labem is certainly longer, as only the direct route (as the crow flies) between Teplice and Roudnice nad Labem has been calculated here.
Air line (approximately)
39 kilometers
21 nautical miles