Des Moines is about 6 times smaller than Saint Petersburg.

Saint Petersburg is approximately 1,439 sq km, while Des Moines (map shows its 58 named neighbourhoods; the area covers the whole city) is approximately 228 sq km, making Des Moines 15.87% the size of Saint Petersburg.
Tip: This to-scale comparison of Saint Petersburg vs. Des Moines 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.