Austin is about 8 times smaller than Ho Chi Minh City.

Ho Chi Minh City is approximately 6,773 sq km, while Austin (map shows its 70 named neighbourhoods; the area covers the whole city) is approximately 829 sq km, making Austin 12.24% the size of Ho Chi Minh City.
Tip: This to-scale comparison of Ho Chi Minh City vs. Austin 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.