The calculated distance (air line) between Saint-Quentin-en-Yvelines and Gif-sur-Yvette is approximately 8 miles respectively 13 kilometers.
By car or train, the actual journey to Gif-sur-Yvette is certainly longer, as only the direct route (as the crow flies) between Saint-Quentin-en-Yvelines and Gif-sur-Yvette has been calculated here.
Air line (approximately)
13 kilometers
7 nautical miles