A property owner in Long Beach once asked me why the number on his lease didn't match the number his architect gave him. His architect measured the space he could actually walk around in. His lease measured something else. Neither was wrong. They were just measuring under different rules, and nobody had told him there were rules.
That gap between "the space I use" and "the space I pay for" is what BOMA standards exist to define. If you lease, own, or manage commercial space, it's worth understanding what those numbers mean before you sign.
What BOMA is
BOMA International — the Building Owners and Managers Association — publishes the measurement standards that most U.S. commercial leases reference. The standards define exactly how to calculate the square footage of a building and the spaces within it, so a landlord in one city and a tenant from another are speaking the same language.
The most commonly cited standard is the BOMA Office Standard (ANSI/BOMA Z65.1). There are separate standards for retail, industrial, multi-unit residential, and mixed-use, each with its own rules. When a lease says "measured per BOMA," it should say which standard and which year — the methodology has been revised several times, and the numbers can differ between versions.
Usable vs. rentable — the distinction that costs money
Two numbers do most of the work in a commercial lease:
Usable area is roughly the space a tenant occupies exclusively — the floor you could actually furnish. It excludes major vertical penetrations like elevator shafts and stairwells.
Rentable area is usable area plus the tenant's proportional share of the building's common areas: lobbies, shared corridors, restrooms, mechanical rooms. This is almost always the number you pay rent on.
The ratio between them is the load factor (sometimes called the add-on or core factor). A building with a 15% load factor means a tenant with 10,000 usable square feet pays rent on 11,500 rentable square feet. On a multi-year lease, that difference is real money, which is exactly why the measurement methodology matters and why it should be documented, not estimated.
A tenant tours a space, mentally measures the room they'll work in, and anchors on that number. The lease then quotes rentable area, which is larger. Nothing improper has happened — but if nobody explains the load factor, it feels like a discrepancy. Documenting both numbers up front prevents the confusion.
Where 3D scanning fits
BOMA calculations depend entirely on accurate boundary measurements: the inside face of walls, the centerlines of demising walls, the footprint of vertical penetrations. Traditionally these came from a tape measure and the original architectural drawings — drawings that, in an older building with years of tenant improvements, may no longer match reality.
A laser scan removes that guesswork. We capture the actual, current geometry of the floor plate, then calculate usable and rentable area directly from measured conditions rather than from drawings that may be decades old. For a landlord, that produces a defensible number. For a tenant, it's a number you can verify. For a broker, it's documentation that holds up if a lease is ever disputed.
The deliverable is typically a dimensioned floor plan with an area calculation table, tied to the specific BOMA standard and year the lease references. If the space is being marketed, the same scan produces the listing floor plan at the same time.
Practical advice before you measure
Name the standard and the year. "BOMA 2017 Office Standard, Method A" is a specification. "BOMA" alone is not. The revision year changes the result.
Measure once, at the source. If a building is being re-tenanted floor by floor, scan the whole floor plate once and derive each suite's numbers from the same dataset. Piecemeal measurements taken years apart drift.
Keep the point cloud. When a tenant reconfigures or a suite is subdivided later, having the original scan means you re-derive areas without another site visit.
Separate the survey from the interpretation. The scan tells you the geometry. Applying the BOMA rules to that geometry is a calculation. A good provider will show you both, so you can see how the rentable number was built.
The short version
BOMA standards exist so everyone measures the same way. Usable is what you occupy; rentable is what you pay for; the load factor is the difference. And whichever side of the lease you're on, the number is only as trustworthy as the measurement behind it. An accurate scan turns "approximately" into "documented" — which is exactly what you want when the number is attached to a contract.
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