Alaska is about 3.9 times bigger than Japan.

Japan is approximately 377,915 sq km, while Alaska is approximately 1,481,348 sq km, making Alaska 292% larger than Japan. Meanwhile, the population of Japan is ~124.2 million people (123.5 million fewer people live in Alaska).
Tip: This to-scale comparison of Japan vs. Alaska uses the Mercator projection, which distorts the size of regions near the poles.
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