Seoul is about 2.1 times bigger than Salt Lake City.

Salt Lake City is approximately 287 sq km, while Seoul is approximately 605 sq km, making Seoul 111% larger than Salt Lake City.
Tip: This to-scale comparison of Salt Lake City vs. Seoul 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.