Warsaw is about 1.3 times bigger than Denver.

Denver is approximately 396 sq km, while Warsaw is approximately 517 sq km, making Warsaw 30% larger than Denver.
Tip: This to-scale comparison of Denver vs. Warsaw 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.