Guernsey is about 4,030 times smaller than New Mexico.

New Mexico is approximately 314,310 sq km, while Guernsey is approximately 78 sq km, making Guernsey 0.02% the size of New Mexico. Meanwhile, the population of New Mexico is ~2.1 million people (2.0 million fewer people live in Guernsey).
Tip: This to-scale comparison of New Mexico vs. Guernsey uses the Mercator projection, which distorts the size of regions near the poles.