The calculated distance (air line) between Zürich (Kreis 10) / Höngg and Rapperswil is approximately 20 miles respectively 31 kilometers.
By car or train, the actual journey to Rapperswil is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 10) / Höngg and Rapperswil has been calculated here.
Air line (approximately)
31 kilometers
17 nautical miles