Hanoi is about 2.6 times bigger than Rome.

Rome is approximately 1,287 sq km, while Hanoi is approximately 3,360 sq km, making Hanoi 161% larger than Rome.
Tip: This to-scale comparison of Rome vs. Hanoi 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.