Slovakia is about 8 times smaller than California.

California is approximately 403,882 sq km, while Slovakia is approximately 49,035 sq km, making Slovakia 12.14% the size of California. Meanwhile, the population of California is ~37.3 million people (31.8 million fewer people live in Slovakia).
Tip: This to-scale comparison of California vs. Slovakia uses the Mercator projection, which distorts the size of regions near the poles.