San Francisco is about 2.5 times smaller than Szczecin.

Szczecin is approximately 301 sq km, while San Francisco (including the city proper only) is approximately 121 sq km, making San Francisco 40.2% the size of Szczecin.
Tip: This to-scale comparison of Szczecin vs. San Francisco uses the Mercator projection, which distorts the size of regions near the poles.
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