San Diego is about 1.6 times bigger than Warsaw.

Warsaw is approximately 517 sq km, while San Diego is approximately 844 sq km, making San Diego 63% larger than Warsaw.
Tip: This to-scale comparison of Warsaw vs. San Diego 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.