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Extreme Measures is a BOMA Floor Measurement Standards expert. We host this help desk as a free resource for the real estate community at large. Neither BOMA or Extreme Measures is responsible for the information, comments or opinions contained herein. For complete information, please refer to the appropriate BOMA publications themselves, available at the BOMA Store Online.

BOMA Office Standards


The "Standard Method for Measuring Floor Area in Office Buildings" is published by BOMA International (The Building Owners and Managers Association) and is approved by ANSI (American National Standards Institute). The Standard is used by building owners, facility managers, leasing professionals, tenants, appraisers, architects, planners, and building measurement professionals to compute floor area in office buildings using an agreed-upon, standard method of measurement.

BOMA International first developed the Standard in 1915. Since then, it has undergone several revisions, the most recently in 1980, 1996 & 2010. BOMA 1980 (ANSI/BOMA Z65.1-1980) and BOMA 1996 (ANSI/BOMA Z65.1-1996) are both in wide use today. BOMA 2010 (ANSI/BOMA Z65.1-2010) is still quite new but gaining popularity.

What about BOMA 1989?

There is a common misperception that BOMA 1989 is a distinct standard unto itself, however this is not the case. In 1989, BOMA republished the BOMA 1980 Standard to include a French translation and a question and answer section called "Answers to 20 Questions Frequently Asked about the BOMA Standard Method of Floor Measurement." The text is otherwise identical to the previous publication and BOMA did not rename or intend to rename the standard.

What are the key differences between the BOMA Office Standards?

Building Common Area is the key feature that distinguishes BOMA 1996 from BOMA 1980. In determining the rentable area of a floor and its comprising tenants, BOMA 1980 employs floor common area only. While straightforward, there are important limitations to consider when using BOMA 1980. For example, tenants residing on floors with large portions of common area are penalized by large gross-up factors. This problem is particularly evident on ground floors, where lobby areas and other building amenities are considered floor common area and are shared by ground floor tenants exclusively. This generally results in exorbitant gross-up factors when compared to "typical" building floors. It is also important to note that BOMA 1980 makes no provisions for floors that do not have tenant areas such as mechanical floors. As a result, BOMA 1980 does not recover rent for such floors at all.

BOMA 1996 employs floor common area (like BOMA 1980) and additionally, building common area. Building common area is comprised of building lobbies, mechanical penthouses and other building amenities. These areas are proportionately shared by all of the tenants in the building resulting in a more equitable distribution of common area in general. The inclusion of non-tenanted floors (such as mechanical floors) and its allocation as building common area generally results in larger total rentable areas and improved recovery of operating costs if compared to BOMA 1980. It is should be noted that an entire building must be measured in order to perform BOMA 1996 rentable area calculations.

Extreme Measures developed this material in response to queries regarding BOMA measuring standards. This information should be used for reference purposes only. Neither BOMA or Extreme Measures Inc. endorses the information provided. For complete information, please refer to the official publications of BOMA International.