Oahu is about 2 times smaller than Yosemite National Park.

Yosemite National Park is approximately 3,027 km² (1,169 sq mi), while Oahu is approximately 1,545 km² (597 sq mi), making Oahu 51.04% the size of Yosemite National Park.
Tip: This to-scale comparison of Yosemite National Park 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.