The calculated distance (air line) between Horgen / Horgen (Dorfkern) and Winterthur is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Winterthur is certainly longer, as only the direct route (as the crow flies) between Horgen / Horgen (Dorfkern) and Winterthur has been calculated here.
Air line (approximately)
29 kilometers
16 nautical miles