Hawaii is about 23 times smaller than Montana.

Montana is approximately 376,979 sq km, while Hawaii is approximately 16,635 sq km, making Hawaii 4.41% the size of Montana. Meanwhile, the population of Montana is ~989,415 people (370,886 more people live in Hawaii).
Tip: This to-scale comparison of Montana vs. Hawaii uses the Mercator projection, which distorts the size of regions near the poles.