Beijing is about 4.2 times bigger than Melbourne.

Melbourne (the 27 councils of metropolitan Melbourne, without the Yarra Ranges, Cardinia, Mornington Peninsula and Nillumbik) is approximately 3,915 sq km, while Beijing is approximately 16,411 sq km, making Beijing 319% larger than Melbourne.
Tip: This to-scale comparison of Melbourne vs. Beijing 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.