The calculated distance (air line) between Zürich (Kreis 6) / Unterstrass and Frauenfeld is approximately 20 miles respectively 33 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 6) / Unterstrass and Frauenfeld has been calculated here.
Air line (approximately)
33 kilometers
18 nautical miles