The calculated distance (air line) between Garðabær and Sauðárkrókur is approximately 133 miles respectively 213 kilometers.
By car or train, the actual journey to Sauðárkrókur is certainly longer, as only the direct route (as the crow flies) between Garðabær and Sauðárkrókur has been calculated here.
Air line (approximately)
213 kilometers
115 nautical miles