The calculated distance (air line) between Magny-les-Hameaux and Le Havre is approximately 102 miles respectively 165 kilometers.
By car or train, the actual journey to Le Havre is certainly longer, as only the direct route (as the crow flies) between Magny-les-Hameaux and Le Havre has been calculated here.
Air line (approximately)
165 kilometers
89 nautical miles