Manchester, New Hampshire is 2.4 times larger than Lowell, Massachusetts.
Area: 38 km2 calculated
Lowell is a city in Middlesex County, Massachusetts, in the United States. With an estimated population of 108,522, it is the fourth-largest city in Massachuetts, after Boston, Worcester, and Springfield, and the second-largest in what the U.S. Census Bureau defines as Boston's metropolitan area. Wikipedia
Area: 90 km2 calculated
Manchester is the largest city in the U.S. state of New Hampshire, the tenth largest city in New England, and the largest city in northern New England, an area comprising the states of Maine, New Hampshire, and Vermont. It was first named by the merchant and inventor Samuel Blodget. Wikipedia