Brunei is around the same size as Delaware.

Delaware is approximately 5,060 sq km, while Brunei is approximately 5,765 sq km, making Brunei 14% larger than Delaware. Meanwhile, the population of Delaware is ~897,934 people (419,880 fewer people live in Brunei).
Tip: This to-scale comparison of Delaware vs. Brunei uses the Mercator projection, which distorts the size of regions near the poles.