Kansas City, Kansas is 41% larger than Des Moines, Iowa.
Area: 235 km2 calculated
Des Moines is the capital and the most populous city in the U.S. state of Iowa. It is also the county seat of Polk County. A small portion of the city extends into Warren County. It was incorporated on September 22, 1851, as Fort Des Moines which was shortened to "Des Moines" in 1857. Wikipedia
Area: 332 km2 calculated
Kansas City is the third-largest city in the state of Kansas, the county seat of Wyandotte County, and the third-largest city of the Kansas City metropolitan area. It is part of a consolidated city-county government known as the "Unified Government". Wikipedia