The calculated distance (air line) between Thun and Zürich (Kreis 12) is approximately 64 miles respectively 102 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 Thun and Zürich (Kreis 12) has been calculated here.
Air line (approximately)
102 kilometers
55 nautical miles