The calculated distance (air line) between Oud-Beijerland and Amersfoort is approximately 47 miles respectively 76 kilometers.
By car or train, the actual journey to Amersfoort is certainly longer, as only the direct route (as the crow flies) between Oud-Beijerland and Amersfoort has been calculated here.
Air line (approximately)
76 kilometers
41 nautical miles