Tehran is about 2.3 times bigger than Riga.

Riga is approximately 304 sq km, while Tehran is approximately 686 sq km, making Tehran 126% larger than Riga.
Tip: This to-scale comparison of Riga vs. Tehran 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.