Phoenix is about 3.4 times bigger than Denver.

Denver is approximately 396 sq km, while Phoenix is approximately 1,342 sq km, making Phoenix 239% larger than Denver.
Tip: This to-scale comparison of Denver vs. Phoenix 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.