Sydney is about 9 times bigger than Venice.

Venice is approximately 415 sq km, while Sydney (the 30 councils of metropolitan Sydney, without the Blue Mountains, Hawkesbury, Wollondilly and the Central Coast) is approximately 3,810 sq km, making Sydney 819% larger than Venice.
Tip: This to-scale comparison of Venice vs. Sydney 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.