Dusseldorf is about 6 times smaller than Rome.

Rome is approximately 1,287 sq km, while Dusseldorf is approximately 217 sq km, making Dusseldorf 16.89% the size of Rome.
Tip: This to-scale comparison of Rome vs. Dusseldorf 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.