Rhode Island is about 1.8 times bigger than Oahu.

Oahu is approximately 1,545 km² (597 sq mi), while Rhode Island is approximately 2,706 sq km, making Rhode Island 75% larger than Oahu.
Tip: This to-scale comparison of Oahu vs. Rhode Island 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.