The calculated distance (air line) between Ouderkerk aan de Amstel and Zwolle is approximately 52 miles respectively 84 kilometers.
By car or train, the actual journey to Zwolle is certainly longer, as only the direct route (as the crow flies) between Ouderkerk aan de Amstel and Zwolle has been calculated here.
Air line (approximately)
84 kilometers
45 nautical miles