22
Global
Height rank
Willis Tower
Chicago
Height

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the architectural top of the building, including spires, but not including antennae, signage, flag poles or other functional-technical equipment. This measurement is the most widely utilized and is employed to define the Council on Tall Buildings and Urban Habitat (CTBUH) rankings of the "World's Tallest Buildings."

1
To Tip:

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the highest point of the building, irrespective of material or function of the highest element (i.e., including antennae, flagpoles, signage and other functional-technical equipment).

527 m / 1,729 ft
2
Architectural:

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the architectural top of the building, including spires, but not including antennae, signage, flag poles or other functional-technical equipment. This measurement is the most widely utilized and is employed to define the Council on Tall Buildings and Urban Habitat (CTBUH) rankings of the "World's Tallest Buildings."

442.1 m / 1,451 ft
3
Occupied:

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the highest occupied floor within the building.

412.7 m / 1,354 ft
1 2 3 Willis Tower Outline
Floors

The number of floors above ground should include the ground floor level and be the number of main floors above ground, including any significant mezzanine floors and major mechanical plant floors. Mechanical mezzanines should not be included if they have a significantly smaller floor area than the major floors below. Similarly, mechanical penthouses or plant rooms protruding above the general roof area should not be counted. Note: CTBUH floor counts may differ from published accounts, as it is common in some regions of the world for certain floor levels not to be included (e.g., the level 4, 14, 24, etc. in Hong Kong).

Above Ground

The number of floors above ground should include the ground floor level and be the number of main floors above ground, including any significant mezzanine floors and major mechanical plant floors. Mechanical mezzanines should not be included if they have a significantly smaller floor area than the major floors below. Similarly, mechanical penthouses or plant rooms protruding above the general roof area should not be counted. Note: CTBUH floor counts may differ from published accounts, as it is common in some regions of the world for certain floor levels not to be included (e.g., the level 4, 14, 24, etc. in Hong Kong).

108
Below Ground

The number of floors below ground should include all major floors located below the ground floor level.

3
Height 442.14 m / 1,451 ft
Floors 108
Official Name

The current legal building name.

Willis Tower
Other Names

Other names the building has commonly been known as, including former names, common informal names, local names, etc.

Sears Tower
Type

CTBUH collects data on two major types of tall structures: 'Buildings' and 'Telecommunications / Observation Towers.' A 'Building' is a structure where at least 50% of the height is occupied by usable floor area. A 'Telecommunications / Observation Tower' is a structure where less than 50% of the structure's height is occupied by usable floor area. Only 'Buildings' are eligible for the CTBUH 'Tallest Buildings' lists.

Building
Status
Completed
Architecturally Topped Out
Structurally Topped Out
Under Construction
Proposed
On Hold
Never Completed
Vision
Competition Entry
Canceled
Proposed Renovation
Under Renovation
Renovated
Under Demolition
Demolished
Completed, 1974
Country

The CTBUH follows the United Nations's definition of Country, and thus uses the lists and codes established by that organization.

City

The CTBUH follows the United Nations's definition of City, and thus uses the lists and codes established by that organization.

Postal Code
60606
Function

A single-function tall building is defined as one where 85% or more of its usable floor area is dedicated to a single usage. Thus a building with 90% office floor area would be said to be an "office" building, irrespective of other minor functions it may also contain.

A mixed-use tall building contains two or more functions (or uses), where each of the functions occupy a significant proportion of the tower's total space. Support areas such as car parks and mechanical plant space do not constitute mixed-use functions. Functions are denoted on CTBUH "Tallest Building" lists in descending order, e.g., "hotel/office" indicates hotel function above office function.

office
Structural Material

Steel
Both the main vertical/lateral structural elements and the floor spanning systems are constructed from steel. Note that a building of steel construction with a floor system of concrete planks or concrete slab on top of steel beams is still considered a “steel” structure as the concrete elements are not acting as the primary structure.

Reinforced Concrete
Both the main vertical/lateral structural elements and the floor spanning systems are constructed from concrete which has been cast in place and utilizes steel reinforcement bars.

Precast Concrete
Both the main vertical/lateral structural elements and the floor spanning system are constructed from steel reinforced concrete which has been precast as individual components and assembled together on-site.

Mixed-Structure
Utilizes distinct systems (e.g. steel, concrete, timber), one on top of the other. For example, a steel/concrete indicates a steel structural system located on top of a concrete structural system, with the opposite true of concrete/steel.

Composite
A combination of materials (e.g. steel, concrete, timber) are used together in the main structural elements. Examples include buildings which utilize: steel columns with a floor system of reinforced concrete beams; a steel frame system with a concrete core; concrete-encased steel columns; concrete-filled steel tubes; etc. Where known, the CTBUH database breaks out the materials used in a composite building’s core, columns, and floor spanning separately.

steel
LEED Recertification Platinum (2019), LEED Gold O+M: Existing Buildings (2016)
Official Website
Height

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the architectural top of the building, including spires, but not including antennae, signage, flag poles or other functional-technical equipment. This measurement is the most widely utilized and is employed to define the Council on Tall Buildings and Urban Habitat (CTBUH) rankings of the "World's Tallest Buildings."

Architectural
442.14 m / 1,451 ft
To Tip
527 m / 1,729 ft
Occupied
412.69 m / 1,354 ft
Observatory
412.69 m / 1,354 ft
Floors Above Ground

The number of floors above ground should include the ground floor level and be the number of main floors above ground, including any significant mezzanine floors and major mechanical plant floors. Mechanical mezzanines should not be included if they have a significantly smaller floor area than the major floors below. Similarly, mechanical penthouses or plant rooms protruding above the general roof area should not be counted. Note: CTBUH floor counts may differ from published accounts, as it is common in some regions of the world for certain floor levels not to be included (e.g., the level 4, 14, 24, etc. in Hong Kong).

108
Floors Below Ground

The number of floors below ground should include all major floors located below the ground floor level.

3
# of Elevators

Number of Elevators refers to the total number of elevator cars (not shafts) contained within a particular building (including public, private and freight elevators).

104
Tower GFA

Tower GFA refers to the total gross floor area within the tower footprint, not including adjoining podiums, connected buildings or other towers within the development.

423,638 m² / 4,560,001 ft²
Rankings
#
22
Tallest in the World
#
3
Tallest in North America
#
3
Tallest in United States
#
1
Tallest in Chicago
#
9
Tallest Office Building in the World
#
2
Tallest Office Building in North America
#
2
Tallest Office Building in United States
#
1
Tallest Office Building in Chicago
#
1
Tallest Steel Building in the World
#
1
Tallest Steel Building in North America
#
1
Tallest Steel Building in United States
#
1
Tallest Steel Building in Chicago
Construction Schedule
1970

Construction Start

1974

Completed

2016

Retrofit Start

2021

Retrofit End

Owner

Current

The Blackstone Group L.P.
Developer
Sears Roebuck and Company
Architect
Structural Engineer
MEP Engineer
Contractor
Morse Diesel International

Property Management

CBRE; EQ Office

Cladding

Elevator

Steel

American Bridge Company

Retrofit Companies Involved

Owner/Developer
The Blackstone Group L.P.
Architect
Structural Engineer
MEP Engineer
EQ Office
Contractor

Artist

Studio Olafur Eliasson

Energy Concept

Rivion

CTBUH Initiatives

28 August 2019 - Building Tour

28 August 2019 - Building Tour

Videos

30 October 2017 | Chicago

Recent developments in the design and construction of progressively taller buildings using engineered timber as a structural material raise important questions about the language that...

Research

25 June 2020

Sae Hwang Oh, Adrian Smith + Gordon Gill Architecture

Beginning in the late 19th century, construction of skyscrapers spread throughout Chicago, New York City, and then the world as demand of space in buildings...

Global News

03 February 2021 | Chicago

United Airlines is shrinking its Willis Tower headquarters, where it has about 30 percent fewer workers than before the COVID-19 pandemic. The airline today confirmed...

About Willis Tower

The Willis Tower (formerly Sears Tower) in Chicago, with its signature black aluminum and bronze-tinted glare-reducing glass, was the tallest building in the world for nearly 25 years. Completed in 1974, Willis Tower set the standard for supertall skyscrapers around the globe, both in its innovative design and graceful styling. With approximately 424,000 square meters of gross floor area, the building is comparatively large for its height, with its foundation and the first 50 floors taking up an entire city block before the building begins to narrow.

The step-back design of the structure was designed by the architects as a direct result of Sears’ space requirements. The designers were required to develop a building that incorporated not only very large office floors, which were necessary to Sears’ operation, but also a variety of smaller floors which would be more suitable for tenants requiring less floor area. These requirements resulted in a bundled tube structure, the first of its kind. This innovative design was not only structurally efficient, but it also managed to be economical as well. It has proven to be a remarkably influential design typology, and has been used in most supertall buildings built since the Willis Tower, including the Burj Khalifa.

An assortment of features has kept the tower active, inviting, and efficient over its operational life. An undulating Alexander Calder sculpture greets office workers in the west lobby. Meanwhile, a 2009 addition to the observation deck affords visitors with vertigo-inducing views of Chicago via “The Ledge,” a series of boxes with transparent floors that extrude from the top of the building. Although the Willis Tower was built in an age before sustainable design matured, the building’s owners have recently implemented several sustainable elements, including low-flow fixtures that conserve more than 38 million liters of water annually, and high-efficiency lighting systems that help curb electrical loads.

Quick Facts

30 October 2017 | Chicago

Recent developments in the design and construction of progressively taller buildings using engineered timber as a structural material raise important questions about the language that...

16 March 2017 | Chicago

Thursday, March 16, 2017. Chicago, United States of America. Hosted in collaboration with the Chicago Architecture Foundation, the first lecture of the series Building Tall...

26 October 2015 | Chicago

Gary Barnett, Extell Development Corporation; Ric Clark, Brookfield Properties; Joseph Moinian, Moinian Group; and Larry Silverstein, Silverstein Properties, discuss development in New York City and...

11 June 2013 | Chicago

From the 1970’s seminal Willis Faber Dumas Ipswich building, through 51 Lime Street London (winner of the CTBUH 2008 Best Tall Building Europe award), to...

11 June 2013 | Chicago

Carmine Bilardello of Willis Group is interviewed by Jeff Herzer during the 2013 CTBUH London Conference at The Brewery, London. Carmine talks about emerging corporate...

20 September 2012 | Chicago

Tony Long of CBRE is interviewed by Jeff Herzer during the 2012 CTBUH Shanghai Congress at the Jin Mao, Shanghai. Tony talks about the management...

25 June 2020

Sae Hwang Oh, Adrian Smith + Gordon Gill Architecture

Beginning in the late 19th century, construction of skyscrapers spread throughout Chicago, New York City, and then the world as demand of space in buildings...

28 October 2019

Stephen Katz, Gensler

Few buildings are as iconic as Willis Tower. Generations of Chicagoans have a collective memory of this building playing a role in their entire lives....

28 October 2019

Carol Willis, The Skyscraper Museum

In both professional circles and in the public eye, the subject of the World’s Tallest Building (WTB) has held the spotlight for more than a...

01 September 2018

Kyoung Sun Moon, Yale University School of Architecture

Tall buildings which began from about 40 m tall office towers in the late 19th century have evolved into mixed-use megatall towers over 800 m....

19 January 2016

Jason Gabel, Marty Carver & Marshall Gerometta, CTBUH

CTBUH has determined that 106 buildings of 200 meters’ height or greater were completed around the world in 2015 – setting a new record for...

24 August 2015

CTBUH Research

Perhaps no element of a tall building is more closely related to the pure pleasure of standing high in the sky and taking in the...

03 February 2021 | Chicago

United Airlines is shrinking its Willis Tower headquarters, where it has about 30 percent fewer workers than before the COVID-19 pandemic. The airline today confirmed...

12 January 2021 | Chicago

EQ Office revealed Atmospheric wave wall, a new cultural landmark and the first public art installation in Chicago by globally acclaimed artist Olafur Eliasson. Prominently...

13 October 2020 | Chicago

Reports of the demise of co-working during the pandemic are greatly exaggerated, if you ask the owner of Willis Tower. In a bet on the...

25 September 2020 | Chicago

Dynegy today announced that it has entered into a multi-year partnership with Chicago's iconic Willis Tower to provide 100% renewable electricity to the Tower. "Sustainability...

18 July 2019 | Chicago

EQ Office, the US office portfolio company owned by Blackstone, has reopened Willis Tower’s Wacker Drive lobby, featuring a new, one-of-a-kind art installation created by...

30 April 2019 | Chicago

Vista Tower reached its final height on April 26 2019, when construction workers poured concrete to form the Chicago skyscraper’s 101st and final floor. That...

28 August 2019

CTBUH Chicago led an illuminating tour of the wholesale renovation of the base of Willis Tower, the largest such construction project to take place since the building’s completion

28 August 2019

CTBUH Chicago led an illuminating tour of the wholesale renovation of the base of Willis Tower, the largest such construction project to take place since the building’s completion

11 July 2019

This special reception will give VIPs the opportunity to let loose in the fantastic setting of Willis Tower (formerly Sears Tower), Chicago’s current tallest building (442 meters).

2 May 2019

CTBUH Moment in History #4 discusses the controversial claim by the Petronas Towers for the title of “World’s Tallest Building” over the record holder at the time, Willis Tower.

28 March 2019

"CTBUH 50th Anniversary: Moments in History #3" explores the impact that CTBUH Chairman Fazlur R. Khan, partner, Skidmore Owings & Merrill, had on the tall building industry.

29 November 2018

Building Tall Lecture Addresses Skyscraper Renovations

The latest event in the Building Tall Lecture Series, hosted by the Chicago Architecture Center and CTBUH, featured a panel on revitalizing iconic skyscrapers.