The calculated distance (air line) between Berndorf and Klagenfurt am Wörthersee is approximately 124 miles respectively 200 kilometers.
By car or train, the actual journey to Klagenfurt am Wörthersee is certainly longer, as only the direct route (as the crow flies) between Berndorf and Klagenfurt am Wörthersee has been calculated here.
Air line (approximately)
200 kilometers
108 nautical miles