The calculated distance (air line) between Falkenhagener Feld and Wannsee is approximately 9 miles respectively 15 kilometers.
By car or train, the actual journey to Wannsee is certainly longer, as only the direct route (as the crow flies) between Falkenhagener Feld and Wannsee has been calculated here.
Air line (approximately)
15 kilometers
8 nautical miles