The calculated distance (air line) between Zürich (Kreis 12) / Schwamendingen-Mitte and Frauenfeld is approximately 18 miles respectively 30 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 12) / Schwamendingen-Mitte and Frauenfeld has been calculated here.
Air line (approximately)
30 kilometers
16 nautical miles