Davis is about 4.7 times smaller than San Francisco.

San Francisco (including the city proper only) is approximately 121 sq km, while Davis (map shows its 53 named neighbourhoods; the area covers the whole city) is approximately 26 sq km, making Davis 21.34% the size of San Francisco.
Tip: This to-scale comparison of San Francisco vs. Davis uses the Mercator projection, which distorts the size of regions near the poles.
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