New Jersey is about 34 times smaller than Afghanistan.

Afghanistan is approximately 652,230 sq km, while New Jersey is approximately 19,211 sq km, making New Jersey 2.95% the size of Afghanistan. Meanwhile, the population of Afghanistan is ~38.3 million people (29.6 million fewer people live in New Jersey).
Tip: This to-scale comparison of Afghanistan vs. New Jersey uses the Mercator projection, which distorts the size of regions near the poles.