Phoenix is about 7 times bigger than Buenos Aires.

Buenos Aires is approximately 203 sq km, while Phoenix is approximately 1,342 sq km, making Phoenix 560% larger than Buenos Aires.
Tip: This to-scale comparison of Buenos Aires 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.