The United States Navy (USN) is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest, most capable navy in the world, with the highest combined battle fleet tonnage. The U.S. Navy has the world's largest aircraft carrier fleet, with eleven in service, one in the reserve fleet, and two new carriers under construction. The service has 322,421 personnel on active duty and 107,577 in the Navy Reserve