The calculated distance (air line) between Zürich (Kreis 3) / Sihlfeld and Luzern is approximately 24 miles respectively 39 kilometers.
By car or train, the actual journey to Luzern is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 3) / Sihlfeld and Luzern has been calculated here.
Air line (approximately)
39 kilometers
21 nautical miles