Rome is about 40 times bigger than Naples.

Naples (map shows its 10 named neighbourhoods; the area covers the whole city) is approximately 32 sq km, while Rome is approximately 1,287 sq km, making Rome 3,940% larger than Naples.
Tip: This to-scale comparison of Naples vs. Rome 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.