The calculated distance (air line) between Zürich (Kreis 3) / Alt-Wiedikon and Schaffhausen is approximately 24 miles respectively 38 kilometers.
By car or train, the actual journey to Schaffhausen is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 3) / Alt-Wiedikon and Schaffhausen has been calculated here.
Air line (approximately)
38 kilometers
21 nautical miles