Oahu is about 1.2 times smaller than Lake Okeechobee.

Lake Okeechobee is approximately 1,890 km² (730 sq mi), while Oahu is approximately 1,545 km² (597 sq mi), making Oahu 81.75% the size of Lake Okeechobee.
Tip: This to-scale comparison of Lake Okeechobee 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.