Vienna is about 3.8 times bigger than Bronx.

Bronx is approximately 109 sq km, while Vienna is approximately 415 sq km, making Vienna 280% larger than Bronx.
Tip: This to-scale comparison of Bronx vs. Vienna 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.