Chicago is about 3.5 times bigger than Irvine.

Irvine (map shows its 24 named neighbourhoods; the area covers the whole city) is approximately 170 sq km, while Chicago is approximately 590 sq km, making Chicago 247% larger than Irvine.
Tip: This to-scale comparison of Irvine vs. Chicago uses the Mercator projection, which distorts the size of regions near the poles.
Our free app, MapSize by MyLifeElsewhere — compare any two places, to scale on your mobile device.