Sydney is about 1.7 times smaller than Shanghai.

Shanghai is approximately 6,341 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 60.08% the size of Shanghai.
Tip: This to-scale comparison of Shanghai 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.