The calculated distance (air line) between Saint-Quentin-en-Yvelines and Clamart is approximately 11 miles respectively 19 kilometers.
By car or train, the actual journey to Clamart is certainly longer, as only the direct route (as the crow flies) between Saint-Quentin-en-Yvelines and Clamart has been calculated here.
Air line (approximately)
19 kilometers
10 nautical miles