The calculated distance (air line) between Saint-Quentin-en-Yvelines and Argenteuil is approximately 16 miles respectively 26 kilometers.
By car or train, the actual journey to Argenteuil is certainly longer, as only the direct route (as the crow flies) between Saint-Quentin-en-Yvelines and Argenteuil has been calculated here.
Air line (approximately)
26 kilometers
14 nautical miles