California is about 15,534 times bigger than Tuvalu.

Tuvalu is approximately 26 sq km, while California is approximately 403,882 sq km, making California 1,553,292% larger than Tuvalu. Meanwhile, the population of Tuvalu is ~11,544 people (37.2 million more people live in California).
Tip: This to-scale comparison of Tuvalu vs. California uses the Mercator projection, which distorts the size of regions near the poles.