Munich is about 4.3 times smaller than Phoenix.

Phoenix is approximately 1,342 sq km, while Munich is approximately 311 sq km, making Munich 23.15% the size of Phoenix.
Tip: This to-scale comparison of Phoenix vs. Munich 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.