One World Trade Center, which is being built where the World Trade Center stood, will reach its height of 541 metres next year. Once completed, it will take the title from the current tallest building in the US, the Willis Tower in Chicago, which measures 441 metres.
The judgement was delivered by the Council on Tall Buildings and Urban Habitats (CTBUH), according to its website.
Debates arose last week over whether a mast atop the building should be counted as part of the height of the building.
The 25 members of the council's height committee finally decided that the mast must be deemed a permanent part of the architectural expression of the building, according to the New York Times.
The original World Trade Center, which was destroyed in the terrorist attacks in September 2001, became the tallest buildings in the US when it opened in 1973. But a year later Chicago's Sears Tower took the title. The Sears Tower was later renamed the Willis Tower.
Currently Burj Khalifa, at 828 metres, in Dubai is the tallest building in the world. While only 234 metres high, CCTV Headquarters in Beijing is named the best tall building worldwide by the CTBUH.