Columbus, Ohio is 4.2 times larger than St. Petersburg, Florida.
Area: 694 km2 calculated
Columbus is the capital of and the largest city in the U.S. state of Ohio. It is the 15th largest city in the United States with a population of 822,553. It is the core city of the Columbus, OH Metropolitan Statistical Area, which encompasses a ten county area. Wikipedia
Area: 166 km2 calculated
St. Petersburg is a city in Pinellas County, Florida, United States. As of the 2013 census estimate, the population was 249,688, making St. Petersburg the 5th most populous city in the state of Florida and the largest city in Florida that is not a county seat. St. Wikipedia