Pittsburgh is about 2.9 times smaller than Athens.

Athens (map shows its 34 named neighbourhoods; the area covers the whole city) is approximately 412 sq km, while Pittsburgh is approximately 143 sq km, making Pittsburgh 34.81% the size of Athens.
Tip: This to-scale comparison of Athens vs. Pittsburgh 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.