San Francisco is about 8 times smaller than Fort Worth.

Fort Worth (map shows its 16 named neighbourhoods; the area covers the whole city) is approximately 911 sq km, while San Francisco (including the city proper only) is approximately 121 sq km, making San Francisco 13.28% the size of Fort Worth.
Tip: This to-scale comparison of Fort Worth 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.