Alaska is about 15 times bigger than South Korea.

South Korea is approximately 99,720 sq km, while Alaska is approximately 1,481,348 sq km, making Alaska 1,386% larger than South Korea. Meanwhile, the population of South Korea is ~51.8 million people (51.1 million fewer people live in Alaska).
Tip: This to-scale comparison of South Korea vs. Alaska uses the Mercator projection, which distorts the size of regions near the poles.