Sydney is about 8 times smaller than Antwerp.

Antwerp (map shows its 62 named neighbourhoods; the area covers the whole city) is approximately 208 sq km, while Sydney is approximately 27 sq km, making Sydney 12.82% the size of Antwerp.
Tip: This to-scale comparison of Antwerp 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.