New Caledonia is about 22 times smaller than California.

California is approximately 403,882 sq km, while New Caledonia is approximately 18,575 sq km, making New Caledonia 4.6% the size of California. Meanwhile, the population of California is ~37.3 million people (37.0 million fewer people live in New Caledonia).
Tip: This to-scale comparison of California vs. New Caledonia uses the Mercator projection, which distorts the size of regions near the poles.