The calculated distance (air line) between Rapperswil and Zürich (Kreis 9) / Altstetten is approximately 19 miles respectively 31 kilometers.
By car or train, the actual journey to Zürich (Kreis 9) / Altstetten is certainly longer, as only the direct route (as the crow flies) between Rapperswil and Zürich (Kreis 9) / Altstetten has been calculated here.
Air line (approximately)
31 kilometers
17 nautical miles