Tucson is about 2.6 times smaller than Houston.

Houston is approximately 1,659 sq km, while Tucson (map shows its 130 named neighbourhoods; the area covers the whole city) is approximately 627 sq km, making Tucson 37.82% the size of Houston.
Tip: This to-scale comparison of Houston vs. Tucson 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.