The calculated distance (air line) between Zürich (Kreis 4) / Hard and Sankt Gallen is approximately 41 miles respectively 65 kilometers.
By car or train, the actual journey to Sankt Gallen is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 4) / Hard and Sankt Gallen has been calculated here.
Air line (approximately)
65 kilometers
35 nautical miles