The calculated distance (air line) between Rapperswil and Zürich (Kreis 3) is approximately 18 miles respectively 28 kilometers.
By car or train, the actual journey to Zürich (Kreis 3) is certainly longer, as only the direct route (as the crow flies) between Rapperswil and Zürich (Kreis 3) has been calculated here.
Air line (approximately)
28 kilometers
15 nautical miles