Tokyo is about 2.1 times smaller than Rome.

Rome is approximately 1,287 sq km, while Tokyo is approximately 619 sq km, making Tokyo 48.08% the size of Rome.
Tip: This to-scale comparison of Rome vs. Tokyo 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.