A Summary of
Building Owners & Managers Association
The purpose of the Standard Method For Measuring
Floor Area in Office Buildings is to permit communication and
computation on a clear and understandable basis. The BOMA Standard
has been the generally accepted method for measuring office space
for many years. It should be noted that this standard can and
should be used in measuring office space in old as well as new
buildings. It is applicable to any architectural design or type
This method measures the actual occupiable
area of a floor or an office suite and is of prime interest to
a tenant in evaluating the space offered by a landlord and in
allocating the space required to house personnel and furniture.
The amount of Usable Area on a multi-tenant floor can vary over
the life of a building as corridors expand and contract and as
floors are remodeled. Usable Area can be converted to Rentable
Area by the use of a conversion factor. The Usable Area of an
office shall be computed by measuring to the finished surface
side of the office side of corridor and other permanent walls,
to the center of the partitions that separate the office from
adjoining Usable Areas, and to the inside finished surface of
the dominant portions of the permanent outer building walls. No
deduction shall be made for columns and projections necessary
to the building.
The Usable Area of a floor shall be equal
to the sum of all Usable Areas on that floor.
This method measures the tenant's pro-rata
portion of the entire office floor, excluding elements of the
building that penetrate through the floor to areas below. The
Rentable Area of a building is fixed for the life of a building
and is not affected by changes in corridor sizes and configuration.
This method is therefore recommended for measuring the total income
producing area of a building and for use in computing the tenant's
pro-rata share of a building for purposes of rent escalation.
The Rentable Area of floor area shall be computed by measuring
to the inside finished surface of the dominant portions of the
permanent outer building walls, excluding any major vertical penetrations
of the floor.
No deduction shall be made for columns and
projections necessary to the building. The Rentable Area of an
office on the floor shall be computed by multiplying the Usable
Area of that office by the quotient of the division of the Rentable
Area of the floor by the Usable Area of the floor resulting in
the R/U Ratio.
The Load Factor is the percentage of space
on a floor that is not usable, expressed as a percent of Usable
Area. It is also known as the Common Area Factor or the Loss Factor.
|Rentable Area ÷
|Load Factor (Load)
||R/U Ratio - 1
|Usable Area x R/U Ratio
|Rentable Area ÷ R/U Ratio
|Usable Area x (1 + Load)