The Council on Tall Buildings and Urban Habitat has decided to measure a building’s height from the level of the “lowest, significant, open-air, pedestrian entrance,” to accommodate multi-use skyscrapers with several main entrances at different levels. The group also has decided to eliminate its height-to-roof category—acknowledging that fewer tall buildings have easily measurable, distinct roof elevations. Under the new criteria, the 800-meter-plus Burj Dubai, currently set to open as the world’s tallest building in January, will now be measured from the lowest of its three main entrances. Also, under the new criteria, the recently completed Trump International Hotel & Towers in Chicago has grown almost 9 m, remeasured from the lower, publicly accessible Chicago Riverwalk. The “extra” height makes it, at 423 m, the sixth-tallest completed building, edging out the 421-m Jin Mao Building in Shanghai. CTBUH’s still-standing measurement categories are: 1) height to architectural top, including spires, but not including antennas, signage, flagpoles or other functional/technical equipment; 2) height to highest occupied floor, not including service or mechanical areas; and 3) height to tip, measured to the highest point of the building. More information is available at