The calculated distance (air line) between Zürich (Kreis 4) / Aussersihl and Frauenfeld is approximately 22 miles respectively 35 kilometers.
By car or train, the actual journey to Frauenfeld is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 4) / Aussersihl and Frauenfeld has been calculated here.
Air line (approximately)
35 kilometers
19 nautical miles