Alaska is about 3.9 times bigger than Montana.

Montana is approximately 376,979 sq km, while Alaska is approximately 1,481,348 sq km, making Alaska 293% larger than Montana. Meanwhile, the population of Montana is ~989,415 people (279,184 fewer people live in Alaska).
Tip: This to-scale comparison of Montana vs. Alaska uses the Mercator projection, which distorts the size of regions near the poles.