San Francisco is about 4.7 times bigger than Davis.

Davis (map shows its 53 named neighbourhoods; the area covers the whole city) is approximately 26 sq km, while San Francisco (including the city proper only) is approximately 121 sq km, making San Francisco 369% larger than Davis.
Tip: This to-scale comparison of Davis vs. San Francisco 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.