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Appraisal Standards

Part of: GLA & Appraisal Standards: The Complete Guide

ANSI Z765-2021: The Square Footage Standard for GLA Measurement

Since March 2022, Fannie Mae and Freddie Mac require ANSI Z765-2021 compliant measurements on all UAD appraisals. ANSI Z765 is the national standard for measuring square footage of a dwelling, defining how to calculate gross living area (GLA), where to draw the line on basements and attics, and what ceiling height counts. Here is exactly what the standard says, where appraisers most often make mistakes, and how to get ANSI compliant measurements done faster.

ANSI Z765 Quick Reference
✓ Counts as GLA
✗ Does NOT count
Above-grade finished rooms
Basements (any finish level)
Bedrooms, kitchens, bathrooms
Attached garages and carports
Hallways and closets (above-grade)
Unfinished attic space
Finished attic (if ≥50% at 7 ft ceiling)
Screened or open porches
Heated/cooled sunrooms (interior access)
Areas without interior access
Each floor measured from exterior walls
Spaces below 5 ft ceiling height

Source: ANSI Z765-2021. Mandatory for Fannie Mae / Freddie Mac UAD appraisals since March 2022.

ANSI Z765-2021 square footage calculator for any floor plan

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What Is ANSI Z765?

ANSI Z765 is a measurement standard published by the American National Standards Institute that defines how to calculate the gross living area (GLA) of a single-family home. It was originally developed by the National Association of Home Builders in the 1990s and has since become the accepted industry standard for residential appraisals.

In March 2022, Fannie Mae and Freddie Mac updated their Selling Guides to require ANSI Z765-compliant measurements on all 1004, 1073, and 1025 appraisal forms submitted through UAD. Before that, many appraisers used their own measurement conventions. That flexibility is now gone for GSE loans.

What ANSI Z765 Requires

The standard sets out several specific rules:

Together, these six rules form the ANSI standards for appraisers measuring residential GLA. Following them produces a defensible, ANSI-compliant GLA figure that meets Fannie Mae and Freddie Mac requirements on all UAD forms (1004, 1073, 1025).

What Does Not Count as GLA

SpaceGLA?Reported How
Basement (finished or unfinished)NoBasement section, BGFA or unfinished sq ft
Attached garageNoGarage/carport section
Unfinished atticNoNot reported in room count
Screened porch / deck / patioNoSite improvements / additional features
Space with ceiling height < 5 ftNoNot counted toward GLA
Exterior-access-only spaceNoMay be noted as additional feature
Three-season room / sunroom (no heat)NoAdditional features, possible adjustment

Several areas commonly cause confusion. Under ANSI Z765, the following are excluded from GLA:

These areas are not ignored in the appraisal. They should be noted and described, but they do not add to the GLA figure reported in the UAD form. Sunrooms and three-season rooms get their own contributory value treatment outside GLA.

The Most Common Mistakes

Based on appraiser feedback, these are the errors that come up most often in ANSI Z765 compliance:

Edge Cases Under ANSI Z765-2021

The standard handles common residential construction cleanly. Where appraisers run into compliance questions is in the non-obvious cases: third floors, finished attics, detached condos, basement ceiling height, and half-stories. Here is how ANSI Z765-2021 treats each.

Third-floor living area

A third floor counts as GLA when it meets the same five requirements as any other level: above-grade, finished, heated and cooled by the home's primary HVAC, accessible from the interior, and meeting the ceiling height rules. The ceiling height rule is where third floors most often trip up compliance. In older homes, third floors are typically tucked under the roof with a pitched ceiling, so at least 50% of the finished area must have a ceiling of 7 feet or higher, and any portion below 5 feet is excluded from the GLA total entirely. Report the qualifying third-floor area on its own level line, not merged with the second floor, and document the ceiling-height measurement in the sketch addendum. See the multi-story measurement guide for the full walkthrough.

Finished attic

ANSI Z765 treats a finished attic the same way as a third floor: it can count as GLA if it meets every standard rule. In practice that means a pull-down attic ladder disqualifies the space because it fails the interior-access rule, an unconditioned attic fails the heated-and-cooled rule, and a finished attic with full pitched ceilings often fails the 50% at 7 feet rule. The renovations that pass are usually dormer-added or gable-end attics with a conditioned space carved out where the usable portion meets the height rule. For the deeper treatment, see attic square footage in appraisals.

Basement ceiling height and finished basement area

Basements are excluded from GLA outright under ANSI Z765-2021, regardless of finish level or ceiling height. The ceiling-height rules still matter for basements, but they apply to the separately reported Basement Finished Area line. To count as basement finished area, the space must be finished, heated and cooled, and meet the same 7-foot minimum with a 5-foot hard floor. A finished basement with a 6'6" ceiling is reported as unfinished basement area for appraisal purposes, even if it has drywall, flooring, and HVAC. See finished basement square footage in appraisals for how to report and adjust for it.

Detached condominiums

Detached condos create an edge case because they are legally condominiums but physically single-family structures. Fannie Mae's instructions distinguish between attached condos (form 1073, measured from the interior of enclosing walls) and detached condos, which follow the same ANSI Z765 exterior-measurement methodology as single-family detached homes. If the unit is free-standing with its own exterior walls, measure it from the exterior and report GLA the same way you would a 1004 property. Reviewers do catch this, and submitting a detached condo with interior measurements is a common compliance rejection.

Bonus room above garage

A finished bonus room above the garage can count as GLA if it is above-grade, accessible from the home's interior (not only via the garage), heated and cooled by the primary HVAC system, and meets the ceiling height minimum over at least 50% of the finished area. Each of these is a common failure point. A bonus room reached only through a garage staircase with no interior hallway connection fails the interior-access rule. A room heated by a standalone mini-split instead of the primary HVAC fails the heated-and-cooled rule. A room with significant sloped ceiling below 5 feet must have that portion excluded from the total. See bonus room square footage in appraisals for the full treatment.

Half-stories and split levels

ANSI Z765-2021 treats a half-story the same as any other finished level: it counts if it meets the rules, and the ceiling height calculation applies to just the finished portion. Split-level homes require each level to be measured and reported separately, with any level that is more than half below grade reported as basement area rather than GLA. The common mistake is treating the lowest level of a split as GLA because it feels like living space. If the finished floor is more than half below the lowest adjacent grade, it is basement area under ANSI Z765, regardless of finish.

Porches, sunrooms, and three-season rooms

Under ANSI Z765, screened porches and open porches are excluded from GLA regardless of finish, because they fail the heated and cooled requirement. A heated and cooled sunroom can count as GLA only if it meets every standard rule: accessible from the home's interior (not only from outside), heated and cooled by the home's primary HVAC system (not a wall unit or space heater), permanently finished walls and ceiling, and meets the 7-foot ceiling height rule. A three-season room with seasonal heating or window units is not GLA, regardless of how finished it looks. When in doubt, report the sunroom or porch separately as a contributory value rather than rolling it into GLA, since reviewers will flag it.

Hallways, bedrooms, and minimum room sizes

Above-grade hallways, closets, stairways, and laundry rooms count as GLA under ANSI Z765 as long as they are part of the finished, heated and cooled, interior-accessible footprint. ANSI Z765 itself does not set a minimum GLA for an individual bedroom; the standard measures total finished area, not room-by-room minimums. Bedroom minimums come from local building codes and Fannie Mae's livable space requirements, not ANSI Z765. For multifamily appraisals on form 1025, the same ANSI Z765 rules apply to each unit's GLA, with hallways inside a unit counted toward that unit's GLA and shared hallways outside the unit excluded. Common areas, lobbies, and shared corridors in multifamily buildings are not GLA for any single unit.

How Floor Plan Tools Speed Up ANSI-Compliant Measurement

Traditional field measurement with a tape or laser involves sketching the home on paper, computing square footage manually, and transcribing the result into your appraisal software. Every step introduces error and takes time.

A floor plan based ANSI Z765 square footage calculator solves this: upload an existing floor plan, trace the perimeter, set a scale reference from one known dimension, and the tool returns a calculated, ANSI Z765-2021 compliant GLA in minutes.

A floor plan measurement tool lets you work from an existing floor plan image (builder plans, listing photos, MLS attachments, or a photo of your own field sketch) and trace the perimeter digitally. If the floor plan came from a 3D scan service, see our CubiCasa vs Matterport comparison to understand how each handles ANSI compliance. You set the scale by clicking two points of a known measurement, and the tool calculates GLA automatically.

The result is a documented, reproducible measurement you can save, revisit, and attach to your work file. For ANSI compliance, that documentation trail matters as much as the number itself.

Get ANSI-compliant GLA from any floor plan in minutes

Upload a floor plan, trace the perimeter, set scale from any known wall length, and get a defensible GLA calculation instantly. Used by appraisers for pre-inspection due diligence and workfile documentation.

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Related Resources

ANSI Z765-compliant GLA from any floor plan image

PlanSnapper applies ANSI Z765 rules automatically, exterior measurements, ceiling height checks, and grade classification built in. Upload your floor plan and get a compliant GLA in minutes.

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Official Sources

Frequently Asked Questions

When did ANSI Z765 become required for appraisals?

Fannie Mae and Freddie Mac made ANSI Z765-compliant measurement mandatory for all UAD appraisals (forms 1004, 1073, and 1025) effective March 1, 2022, via Selling Guide announcement SEL-2021-09.

Does ANSI Z765 apply to FHA loans?

FHA has its own square footage guidance separate from ANSI Z765, and many state and local jurisdictions (including Alabama, Arizona, Kentucky, Maryland, and Minnesota) follow the ANSI Z765-2021 standard for residential appraisals as adopted by Fannie Mae and Freddie Mac. FHA guidelines are broadly similar (above-grade finished area, exterior measurements, minimum ceiling height) and many appraisers apply ANSI Z765 to FHA assignments by default to maintain consistency.

What is the minimum ceiling height under ANSI Z765?

Finished space must have at least 7 feet of ceiling height to count toward GLA. For sloped or vaulted ceilings, at least 50% of the finished area must reach 7 feet. Any portion with a ceiling below 5 feet is completely excluded.

Does ANSI Z765 apply to condominiums?

ANSI Z765 applies primarily to single-family detached homes. For condos (form 1073), Fannie Mae requires ANSI-compliant measurement of interior finished area, measured from the interior of enclosing walls, not exterior, which is a specific exception to the single-family standard.

Can a finished walkout basement count as GLA under ANSI Z765?

No. A walkout basement is still below-grade under ANSI Z765. Grade is determined by the lowest finished ground level touching the foundation exterior. Even a fully finished, light-filled walkout level is excluded from GLA and must be reported separately on the appraisal form.

How does ANSI Z765 handle bonus rooms above the garage?

A finished bonus room above the garage can count as GLA if it meets all requirements: above-grade, finished, accessible from the home interior, heated and cooled, and meeting ceiling height minimums. The ceiling height rule is the most common compliance issue, areas with sloped ceilings below 5 ft must be excluded from the total.

What is the difference between ANSI Z765 and gross living area?

ANSI Z765 is the standard that defines how gross living area (GLA) must be measured. GLA is the resulting number. Using ANSI Z765 correctly gives you a GLA figure that meets Fannie Mae and Freddie Mac requirements. Without the standard, different appraisers calculating GLA might arrive at different numbers for the same property.

How is a third-floor living area handled under ANSI Z765-2021?

A third floor counts as GLA when it meets the same rules as any other level: above-grade, finished, heated and cooled by the primary HVAC, interior-accessible, and meeting the 7-foot ceiling rule over at least 50% of the finished area. In older homes, third floors often sit under a pitched roof, so portions below 5 feet must be excluded entirely. Report the qualifying third-floor area on its own line in the sketch addendum, not merged with the second floor.

Does a finished attic count as GLA under ANSI Z765?

A finished attic can count as GLA if it meets every standard rule: above-grade, finished, heated and cooled by the primary HVAC system, accessible from the interior through permanent stairs (not a pull-down ladder), and has a ceiling of at least 7 feet over 50% or more of the finished area. Attics with pull-down access, space heaters instead of central HVAC, or low pitched ceilings below the height minimums are excluded.

How does ANSI Z765 treat detached condominiums?

Detached condos are measured from the exterior following the same ANSI Z765 methodology as single-family detached homes, not the interior-wall methodology used for attached condos on form 1073. If the unit is free-standing with its own exterior walls, treat it like a 1004 property and report GLA based on exterior measurements. Reviewers will flag detached condos submitted with interior measurements.

What is the minimum ceiling height for a finished basement under ANSI Z765?

Basements are excluded from GLA regardless of ceiling height. For the separately reported basement finished area, the same height rules apply: at least 7 feet over 50% of the finished area, and any portion below 5 feet is excluded. A finished basement with a 6 foot 6 inch ceiling is reported as unfinished basement area, even if it has drywall, flooring, and HVAC.

Do built-in bookshelves and fixed cabinetry count toward square footage under ANSI Z765?

Yes. Built-in bookshelves, kitchen cabinetry, fixed entertainment units, and similar permanent built-ins are part of the room's interior footprint and count toward GLA because GLA is measured from the exterior wall to exterior wall, not from the usable floor space inside. Removing or installing a built-in does not change the GLA. The same applies to fireplaces, stair stringers, and load-bearing interior walls: they are inside the perimeter and inside the GLA.

How does ANSI Z765 handle sunken living rooms and changes in floor level on the same story?

Sunken rooms and other minor changes in floor level on the same finished story are included in GLA for that story as long as the area is above-grade, finished, heated and cooled, accessible from the interior, and meets the ceiling height rule for the lowered space. The lowered floor does not reclassify the room as basement. Measure the full floor area of the story from the exterior walls; the dropped floor is part of that footprint.

What is the difference between Gross Building Area (GBA) and Gross Living Area (GLA) under Fannie Mae rules?

Gross Living Area (GLA) is the finished, above-grade, heated and cooled square footage of a dwelling, measured to ANSI Z765-2021. Gross Building Area (GBA) is the total finished and unfinished square footage of the entire building, including basements, attached garages, and finished or unfinished space below grade. Fannie Mae uses GLA on the 1004 single-family form. GBA is more relevant for 2-4 unit properties on form 1025, where the finished basement area of an income unit can be included in GBA but is still excluded from GLA.

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