West Virginia is about 1.2 times smaller than Serbia.

Serbia is approximately 77,474 sq km, while West Virginia is approximately 62,361 sq km, making West Virginia 80.49% the size of Serbia. Meanwhile, the population of Serbia is ~6.7 million people (4.9 million fewer people live in West Virginia).
Tip: This to-scale comparison of Serbia vs. West Virginia uses the Mercator projection, which distorts the size of regions near the poles.