The calculated distance (air line) between Sauðárkrókur and Reykjavík is approximately 129 miles respectively 208 kilometers.
By car or train, the actual journey to Reykjavík is certainly longer, as only the direct route (as the crow flies) between Sauðárkrókur and Reykjavík has been calculated here.
Air line (approximately)
208 kilometers
112 nautical miles