Taipei is about 2.5 times smaller than Tehran.

Tehran is approximately 686 sq km, while Taipei is approximately 272 sq km, making Taipei 39.62% the size of Tehran.
Tip: This to-scale comparison of Tehran vs. Taipei 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.