Davis is about 1.2 times smaller than San Mateo.

San Mateo is approximately 31 sq km, while Davis (map shows its 53 named neighbourhoods; the area covers the whole city) is approximately 26 sq km, making Davis 82.18% the size of San Mateo.
Tip: This to-scale comparison of San Mateo vs. Davis 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.