San Jose, California is 100% 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: 470 km2 calculated
San Jose is the third-largest city in California, the tenth-largest in the United States, and the county seat of Santa Clara County. San Jose is the largest city within Silicon Valley, which is a major component of the greater Bay Area. It is the largest city in Northern California. Wikipedia