The calculated distance (air line) between Saint-Quentin-en-Yvelines and Amiens is approximately 79 miles respectively 127 kilometers.
By car or train, the actual journey to Amiens is certainly longer, as only the direct route (as the crow flies) between Saint-Quentin-en-Yvelines and Amiens has been calculated here.
Air line (approximately)
127 kilometers
69 nautical miles