Detroit is about 7 times smaller than Moscow.

Moscow (map shows its 125 districts within the pre-2012 boundary; the area includes New Moscow) is approximately 2,562 sq km, while Detroit (map shows its 92 named neighbourhoods; the area covers the whole city) is approximately 359 sq km, making Detroit 14.03% the size of Moscow.
Tip: This to-scale comparison of Moscow vs. Detroit 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.