The calculated distance (air line) between Sirnach and Zürich (Kreis 12) is approximately 20 miles respectively 32 kilometers.
By car or train, the actual journey to Zürich (Kreis 12) is certainly longer, as only the direct route (as the crow flies) between Sirnach and Zürich (Kreis 12) has been calculated here.
Air line (approximately)
32 kilometers
17 nautical miles