Supertall and megatall skyscrapers

The two thresholds

The Council on Vertical Urbanism, which keeps the reference lists, sorts tall buildings into three bands. A skyscraper starts at 150 m. A supertall is 300 m or taller. A megatall is 600 m or taller. The measurement is architectural height, from the lowest significant pedestrian entrance to the structural top, with spires counted and antennas left out. The 150 m line belongs to the definition of a skyscraper; this page is about the two bands above it.

The thresholds are round numbers and nothing about physics changes at exactly 300 m. What they do is sort buildings that behave alike: a 320 m office tower and a 180 m one are different engineering problems.

How many there are, and where

Roughly 250 completed buildings stand 300 m or taller, spread over about 70 cities. China has the most by a wide margin with around 140, then the United Arab Emirates with about 38 and the United States with about 34. Dubai leads the cities at roughly 33, ahead of Shenzhen at 22 and New York City at 18. The counts move every few months as buildings top out, so check a database for the current figure.

The geography flipped inside one generation. Every supertall built before 1990 was American, and the United States held the lead until China passed it in the 2010s. Most supertalls finished since 2000 are in Asia or the Gulf, and the cities with the most skyscrapers page shows how far that went.

The first supertall

The Chrysler Building in New York reached 319 m in 1930 and was the first building past 300 m. The Empire State Building took it to 381 m the next year. The first supertall outside the United States was the Bank of China Tower in Hong Kong in 1990, where the international wave starts.

The four megatalls

Four completed buildings pass 600 m:

• Burj Khalifa, 828 m, 163 floors, Dubai 🇦🇪, 2010
• Merdeka 118, 679 m, 118 floors, Kuala Lumpur 🇲🇾, 2023
• Shanghai Tower, 632 m, 128 floors, Shanghai 🇨🇳, 2015
• Makkah Royal Clock Tower, 601 m, 120 floors, Mecca 🇸🇦, 2012

The gap is large. Burj Khalifa is 149 m taller than Merdeka 118 in second place, and the fifth-tallest building in the world misses the 600 m line by a single meter. Around 2015 the trade press expected a dozen megatalls by 2020. Three arrived, with proposals canceled and others cut down to supertall height once the costs came in.

What changes above 300 m

Below about 300 m a frame can be designed mainly against gravity, with wind as a load to check. Above it the order reverses: wind decides the shape and the stiffness, because the forces grow faster than the height and occupants notice sway long before anything is near failing. Tapered profiles, rounded corners and openings cut through the top break up the vortices that form as air peels off a flat face. Our page on whether skyscrapers sway covers that side in detail. The thin residential towers near Central Park are the hard case: several pass 400 m on footprints around 20 m wide, and need a damper near the top to keep the motion tolerable.

The structure concentrates in the middle. A supertall usually has a thick reinforced-concrete core around the elevators and stairs, and that core carries far more of the lateral load than the one in a shorter tower. To keep it from working alone, engineers tie it to the perimeter columns with outriggers, deep beams or trusses one or two stories tall that run out from the core at intervals up the building. They make the whole footprint resist bending instead of the core alone, which lets a slender tower stay stiff without filling the floor plate with bracing. Shanghai Tower wraps a rotating glass skin around that system, and the twist cuts the wind load enough to pay for itself.

Elevators force a redesign of their own. One shaft running the full height wastes too much floor area and a cable can only hang so far, so tall towers split the trip: express cars run to sky lobbies where passengers change to local cars, and double-deck cabins serve two floors per stop. Mechanical floors multiply for the same reason. Water cannot be pumped the whole way in one lift, so plant rooms sit every 15 to 20 stories, each taking rentable area.

Why the top is often empty

The headline height of a supertall is often not a height anyone can stand at. The Council on Vertical Urbanism calls the distance between the highest occupied floor and the architectural top vanity height, and it averages about 13 percent across the hundred tallest buildings and around 20 percent among megatalls. On the Burj Khalifa the figure is 244 m, nearly 30 percent of the building, because the upper section is spire and plant rather than rooms.

Spires are not pure decoration. They carry broadcast equipment and window-washing rigs. But they also buy rank cheaply, which is why the counting rules matter: a structure whose vanity height passes 50 percent is reclassified as a tower and drops off the building rankings. The tallest-building page explains how the same rule decided the 1998 record.