Texas is about 178 times bigger than Sydney.

Sydney (the 30 councils of metropolitan Sydney, without the Blue Mountains, Hawkesbury, Wollondilly and the Central Coast) is approximately 3,810 sq km, while Texas is approximately 678,052 sq km, making Texas 17,698% larger than Sydney.
Tip: This to-scale comparison of Sydney vs. Texas 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.