Indianapolis is about 1.7 times smaller than London.

London (including the 32 boroughs of greater London) is approximately 1,572 sq km, while Indianapolis is approximately 935 sq km, making Indianapolis 59.48% the size of London.
Tip: This to-scale comparison of London 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.