Indianapolis is about 2.7 times bigger than Atlanta.

Atlanta (map shows its 114 named neighbourhoods; the area covers the whole city) is approximately 350 sq km, while Indianapolis is approximately 935 sq km, making Indianapolis 167% larger than Atlanta.
Tip: This to-scale comparison of Atlanta vs. Indianapolis 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.