El Salvador is about 584 times bigger than Norfolk Island.

Norfolk Island is approximately 36 sq km, while El Salvador is approximately 21,041 sq km, making El Salvador 58,347% larger than Norfolk Island. Meanwhile, the population of Norfolk Island is ~1,748 people (6.6 million more people live in El Salvador).
Tip: This to-scale comparison of Norfolk Island vs. El Salvador uses the Mercator projection, which distorts the size of regions near the poles.