The calculated distance (air line) between Ouderkerk aan de Amstel and The Hague is approximately 30 miles respectively 48 kilometers.
By car or train, the actual journey to The Hague is certainly longer, as only the direct route (as the crow flies) between Ouderkerk aan de Amstel and The Hague has been calculated here.
Air line (approximately)
48 kilometers
26 nautical miles