The calculated distance (air line) between Richterswil and Zürich (Kreis 9) is approximately 16 miles respectively 26 kilometers.
By car or train, the actual journey to Zürich (Kreis 9) is certainly longer, as only the direct route (as the crow flies) between Richterswil and Zürich (Kreis 9) has been calculated here.
Air line (approximately)
26 kilometers
14 nautical miles