Alaska is about 13 times bigger than Bulgaria.

Bulgaria is approximately 110,879 sq km, while Alaska is approximately 1,481,348 sq km, making Alaska 1,236% larger than Bulgaria. Meanwhile, the population of Bulgaria is ~6.9 million people (6.2 million fewer people live in Alaska).
Tip: This to-scale comparison of Bulgaria vs. Alaska uses the Mercator projection, which distorts the size of regions near the poles.