New South Wales is about 1.2 times smaller than South Australia.

South Australia is approximately 984,321 km² (380,048 sq mi), while New South Wales is approximately 801,150 km² (309,326 sq mi), making New South Wales 81.39% the size of South Australia.
Tip: This to-scale comparison of South Australia vs. New South Wales 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.