Delaware is about 1.8 times smaller than Puerto Rico.

Puerto Rico is approximately 9,104 sq km, while Delaware is approximately 5,060 sq km, making Delaware 55.58% the size of Puerto Rico. Meanwhile, the population of Puerto Rico is ~3.1 million people (2.2 million fewer people live in Delaware).
Tip: This to-scale comparison of Puerto Rico vs. Delaware uses the Mercator projection, which distorts the size of regions near the poles.