The calculated distance (air line) between Zürich (Kreis 12) / Schwamendingen-Mitte and Sankt Gallen is approximately 38 miles respectively 60 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 12) / Schwamendingen-Mitte and Sankt Gallen has been calculated here.
Air line (approximately)
60 kilometers
33 nautical miles