BOMA Standards   

Building Owners and Managers Association

For over a 100 years, BOMA International has set the standard for measuring buildings. In 1915, BOMA first published the Standard Method of Floor Measurement for Office Buildings, an accepted and approved methodology by the American National Standards Institute. Throughout the years, the standard has been revised to reflect the changing needs of the real estate market and the evolution of office building design. Today, BOMA International is the secretariat of a suite of measurement standards: 

Standard Methods of Calculation

  • BOMA Standard for OFFICE Buildings (ANSI/BOMA Z65.1 -2017)
    • The objective of the office standard is to provide a uniform basis for measuring Rentable Area in both existing and new multi story, multiple occupant buildings by taking a building-wide approach to floor area measurement. There are two methods within the standard that could be used to calculate the load factor used to assign common area among tenants used to calculate the Rentable Area.
      • METHOD A - Legacy Method (multiple add-on factors - per floor)​
      • ​METHOD B - Single Load Factor (entire building)

  • BOMA Standard for INDUSTRIAL Buildings (ANSI/BOMA Z65.2-2019)
    • ​The objective of this standard is to measure space for the calculation of Rentable Area in both new and existing industrial spaces.  With a single measurement methodology this standard includes some unenclosed features in the calculations.

  • ​​BOMA Standard for RETAIL Buildings (ANSI/BOMA Z65.5-2020)
    • This standard of measurement is intended for application to buildings containing retail type occupancies relevant to both new and existing buildings whether single or multiple stories. Gross Leasable Area is clearly defined and this standard may be used for a partial measure or complete building measurement.

  • BOMA Standard for MULTI-FAMILY & HOSPITALITY Buildings
         (ANSI/BOMA Z65.4-2023)
  • ​This standard provides an unequivocal direct measure of the physical size of the floor area of a multi unit-residential Buildings and Hotels with a strong focus on determining Living Areas.
    • Gross Method of Measurement
    • Net Method of Measurement
  • ​​BOMA Standard for GROSS AREA of a Building (ANSI/BOMA Z65.5-2018)
    • ​The Exterior Gross Area is the total floor area contained within the measure line. - generally the outside surface of the exterior enclosure of a building - including structured parking. Use for single tenant Offie Buildings as well as Mixed-Use Properties.
  • BOMA Standard for MIXED USE Properties (ANSI/BOMA Z65.6-2021)
    • ​Written for properties that don't fit in to one TYPE of building BOMA International developed this standard to address those building that have multiple uses and components including but not limited to Retail, Office Residential, etc, The main purpose of this standard is to identify Mixed-Use Common Areas and fairly proportion those areas to the appropriate users.  This is not a stand alone standard and relies on the Suite of BOMA Standards in order to correctly apply.


Square Footage - Method for Calculating: ANSI Z765-2013

One of the most important indicators of a home’s worth is its square footage. An American National Standard from the National Association of Home Builders (NAHB) Research Center helps homeowners and real estate professionals make accurate appraisals of a property’s size. ANSI Z765-2003, Single-Family Residential Buildings - Square Footage - Method for Calculating, suggests measuring and multiplying the home’s exterior dimensions, then subtracting unfinished space, rooms that are not usable year-round, and rooms with a sloping ceiling. An additional differentiation is made between above-grade and below-grade square footage. Armed with an accurate appraisal, sellers can decide if renovations and other home improvement projects will add substantially to the worth of their property.


The Real Estate market centers on a key piece of information, square footage. This is important for new construction as well as existing buildings. Using our guaranteed accurate as-built plans and CAD file, we can easily calculate useable area, rentable area, gross leasable area and gross square footages to industry accepted BOMA standards or standards of your choice. We are versed in industry accepted standards for the Commercial, Retail, Industrial, Residential, Mixed Use and Condominium properties. Accurate square footage numbers are crucial to any Real Estate transaction whether it is buying, selling, leasing, tax appraisals, building management services, or construction.  The truth will set you free!