The calculated distance (air line) between Zürich (Kreis 11) / Affoltern and Kriens is approximately 29 miles respectively 46 kilometers.
By car or train, the actual journey to Kriens is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 11) / Affoltern and Kriens has been calculated here.
Air line (approximately)
46 kilometers
25 nautical miles