The calculated distance (air line) between Flawil and Zürich (Kreis 3) is approximately 32 miles respectively 52 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 Flawil and Zürich (Kreis 3) has been calculated here.
Air line (approximately)
52 kilometers
28 nautical miles