What is the difference between ANSI Z765 and BOMA square footage standards?

ANSI Z765 is the residential standard measuring gross living area (GLA) from exterior walls for above-grade finished space. BOMA standards apply to commercial buildings and use different measurement boundaries. The two standards are not interchangeable.

Which standard do appraisers use — ANSI or BOMA?

Residential appraisers use ANSI Z765. Fannie Mae and Freddie Mac require ANSI Z765 compliance on loans they purchase. BOMA standards are used by commercial property managers, landlords, and commercial appraisers.

Can the same property be measured under both ANSI and BOMA?

Technically yes, but the results will differ. Mixed-use or live-work properties may have residential portions measured under ANSI Z765 and commercial portions under BOMA. Each standard must be applied to the appropriate space type.

How much does ANSI Z765 cost compared to BOMA square footage standards?

ANSI Z765 and BOMA square footage standards have different pricing models — one may charge per user, per project, or via annual subscription, while the other may offer a free tier or pay-per-use option. Check the comparison table above for current pricing details and which offers better value for your volume of work.

Which is easier to use — ANSI Z765 or BOMA square footage standards?

Ease of use depends on your starting point. ANSI Z765 tends to fit one type of user or workflow, while BOMA square footage standards is designed for another. If you are working from an existing floor plan PDF and need to calculate square footage quickly, a browser-based tool like PlanSnapper may reduce the learning curve entirely — no software installation required.

Do I need ANSI Z765 or BOMA square footage standards if I already have a floor plan PDF?

If you already have a floor plan as a PDF or image, you may not need either tool. PlanSnapper lets you upload the PDF directly and trace walls in your browser to calculate GLA — no software installation required. Both ANSI Z765 and BOMA square footage standards are most useful for creating sketches from scratch or capturing measurements in the field.

Which works better for calculating GLA — ANSI Z765 or BOMA square footage standards?

Both ANSI Z765 and BOMA square footage standards can support GLA calculation, but the workflow differs. One may require field measurement and sketch entry while the other may allow importing existing floor plans. If your starting point is an existing PDF or image floor plan, PlanSnapper provides a faster path — upload, trace, and get the GLA figure without entering either tool's workflow.

Does ANSI Z765 apply to commercial properties?

No. ANSI Z765 is designed specifically for single-family residential properties and defines gross living area for residential appraisal purposes. Commercial properties use different standards — BOMA (Building Owners and Managers Association) is the primary standard for office and commercial buildings. Mixing the two standards produces non-comparable square footage figures.

What happens if a residential property was measured under BOMA instead of ANSI Z765?

A residential property measured under BOMA may report a different square footage than one measured under ANSI Z765. BOMA measurements may include areas that ANSI Z765 excludes from GLA (such as garages or below-grade space) or use interior rather than exterior dimensions. An appraiser relying on a BOMA-measured figure for a residential GLA report would need to re-measure using ANSI Z765 methodology.

Compare · 8 min read

ANSI Z765 vs BOMA: Which Square Footage Standard Applies to Your Property?

ANSI Z765 and BOMA (Building Owners and Managers Association) are both square footage measurement standards, but they apply to completely different property types. Understanding which standard applies to your property is the first step to an accurate measurement.

The short version

ANSI Z765: Applies to single-family residential properties. Required for most mortgage appraisals in the US. Defines Gross Living Area (GLA).
BOMA: Applies to commercial office, retail, and industrial buildings. Defines rentable area, usable area, and load factors.

ANSI Z765 vs BOMA: at a glance

	ANSI Z765	BOMA
Property type	Single-family residential	Commercial (office, retail, industrial)
Key metric	Gross Living Area (GLA)	Rentable / usable area
Required for	Mortgage appraisals (Fannie/Freddie)	Commercial leases
Basement	Excluded from GLA	May be included (depends on standard)
Garage	Excluded	May be included

ANSI Z765 overview

ANSI Z765 is the American National Standard for measuring single-family residential buildings. It defines Gross Living Area (GLA) as the finished, heated, above-grade living area. Key rules include: below-grade space (including finished basements) does not count as GLA regardless of finish level; garage space does not count; areas must meet minimum ceiling height requirements (generally 5 feet sloped, 7 feet flat) to qualify.

Most residential mortgage appraisals in the United States require ANSI Z765-compliant GLA measurements. Fannie Mae and Freddie Mac both require ANSI Z765 compliance in their appraisal guidelines.

BOMA standards overview

BOMA publishes multiple standards for different commercial property types: the Office Buildings standard, the Retail Buildings standard, the Industrial Buildings standard, and others. BOMA measurements focus on rentable and usable area rather than living area — concepts that don't apply to single-family homes.

BOMA uses a floor-based measurement approach with load factors applied to allocate common area to tenants. This is meaningless for residential use but essential for commercial lease negotiations.

Condominiums and mixed-use

Condominiums fall in a middle ground. ANSI Z765 applies to individual condo units for appraisal purposes. However, common areas in the condo building may be measured under BOMA or other commercial standards. When appraising a condo, the GLA of the unit is measured per ANSI Z765; the building's common areas are not included in GLA.

Already have the floor plan?

PlanSnapper is built for ANSI Z765 residential measurement — it calculates the above-grade GLA from a floor plan. For residential properties, upload the floor plan and trace the exterior walls to get the ANSI-compliant GLA.

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