The calculated distance (air line) between Olten and Zürich (Kreis 9) / Altstetten is approximately 27 miles respectively 44 kilometers.
By car or train, the actual journey to Zürich (Kreis 9) / Altstetten is certainly longer, as only the direct route (as the crow flies) between Olten and Zürich (Kreis 9) / Altstetten has been calculated here.
Air line (approximately)
44 kilometers
24 nautical miles