Oahu is about 1.7 times smaller than Luxembourg.

Luxembourg is approximately 2,586 sq km, while Oahu is approximately 1,545 km² (597 sq mi), making Oahu 59.74% the size of Luxembourg.
Tip: This to-scale comparison of Luxembourg vs. Oahu uses the Mercator projection, which distorts the size of regions near the poles.
Our free app, MapSize by MyLifeElsewhere — compare any two places, to scale on your mobile device.