Chicago is about 1.6 times smaller than Sao Tome and Principe.

Sao Tome and Principe is approximately 964 sq km, while Chicago is approximately 590 sq km, making Chicago 61.18% the size of Sao Tome and Principe.
Tip: This to-scale comparison of Sao Tome and Principe vs. Chicago uses the Mercator projection, which distorts the size of regions near the poles.