Learn · Square Footage Basics · 6 min read

Part of: GLA & Appraisal Standards: The Complete Guide

What Counts as Square Footage in a House?

Square footage sounds simple until you start measuring. Not every room counts. Not every level counts the same way. Appraisers, lenders, and tax assessors all use specific rules to determine what makes it into the official number. Here is what counts, what does not, and why it matters whether you are buying, selling, or refinancing — including for a home equity loan where GLA directly affects how much you can borrow.

The standard used for appraisals: ANSI Z765

The most widely used standard in residential real estate is ANSI Z765-2021, published by the American National Standards Institute. Fannie Mae and Freddie Mac require appraisers to follow it for most conforming loans, which means it effectively governs what counts as square footage for the vast majority of home sales and refinances. Government-backed loans add additional layers — FHA appraisals have specific square footage requirements that can affect what qualifies as a bedroom or livable space.

The key concept under ANSI Z765 is Gross Living Area (GLA): the finished, above-grade, heated living space of a home. GLA is measured from the exterior using finished exterior dimensions, not interior room measurements. Only GLA is counted as square footage for appraisal purposes.

Quick reference: counts vs. does not count

Space	Counts as GLA?	Rule
Finished living rooms, bedrooms, kitchens	✅ Yes	Above-grade, finished, heated
Finished bonus room above garage	✅ Yes (if meets ceiling height)	Must be finished, heated, accessible
Finished basement	❌ No	Below-grade — reported separately
Unfinished basement	❌ No	Below-grade and unfinished
Attached garage	❌ No	Not living space
Enclosed porch / sunroom	⚠️ Depends	Only if heated by primary HVAC, fully finished
Screened porch	❌ No	Not enclosed or heated
Deck or patio	❌ No	Exterior only
Attic (unfinished)	❌ No	Not finished living space
Attic (finished, 7 ft ceiling)	✅ Yes	Must meet ceiling height rules
Loft	✅ Yes (if meets rules)	Finished, above-grade, accessible
Vaulted ceiling area	✅ Yes	Measured at floor level, not ceiling

What counts as square footage

Finished above-grade rooms

Living rooms, dining rooms, kitchens, bedrooms, bathrooms, hallways, closets, and laundry rooms that are above grade (at or above ground level), finished, and heated all count toward GLA. This includes areas that are fully enclosed, have finished walls, floors, and ceilings, and are usable year-round.

Finished above-grade bonus rooms

A finished room above the garage, a finished flex space over a porch, or any other fully finished room that is above grade and connected to the main living area typically counts, provided it meets the ceiling height requirement. Some appraisers require the space to be accessible via standard interior stairs, not a pull-down ladder. For a full breakdown of how these spaces are handled, see the bonus room square footage appraisal guide.

Finished areas in split-level and raised-ranch homes

Split-level homes require careful analysis of which levels are above grade. A level that is partially below grade may count if it meets the "finished and above-grade on at least one side" threshold depending on local appraiser practice and the specific standard being applied.Bi-level (raised ranch) homes are particularly common in this gray zone: most lower levels in a bi-level are below grade on at least one wall and therefore classified as below-grade finished area, not GLA — even with a walkout.

What does NOT count as square footage

Basements (finished or unfinished)

This surprises many homeowners: finished basements do not count toward GLA under ANSI Z765, even if they are beautifully finished with a full bathroom, bedroom, and home theater. Below-grade space is reported separately in an appraisal and assigned a different value per square foot, typically lower than above-grade GLA.

A space is "below grade" if any portion of the exterior wall is below the surrounding ground level. Walkout basements where one wall is fully exposed still count as below grade under strict ANSI Z765 interpretation, though some appraisers and markets treat walkout basements more generously.

Attached garages

Garages do not count toward GLA, even when finished, drywalled, and climate-controlled. A garage is a garage. The exception is a conversion: if a garage has been fully converted to living space (permitted, finished, and heated like the rest of the home), it may count depending on local market practice and whether permits were pulled. See our full guide on garage conversion square footage for what appraisers require. More broadly, unpermitted square footage creates real appraisal and lending complications that buyers and sellers need to understand.

Unheated spaces

Screened porches, sunrooms without year-round heating, three-season rooms, and similar spaces do not count toward GLA because they are not usable year-round as living space. A fully enclosed, heated sunroom with HVAC may count in some markets. An unheated screened porch does not.

Unfinished attic space

An unfinished attic does not count. A finished attic may count, but only the portion that meets the ceiling height requirement.

Decks and patios

Outdoor decks, patios, and covered porches that are open to the elements do not count toward GLA. They add value and are noted in an appraisal, but they are not included in the square footage figure. Swimming pools are treated the same way — a site improvement that contributes to value but does not add to GLA.

The ceiling height rule

Under ANSI Z765, finished floor area only counts when the ceiling is at least 5 feet high. For areas with sloped ceilings (like finished attics, cape cods, and half-stories), the rules are:

At least 50% of the finished floor area must have a ceiling height of 7 feet or more
No portion with a ceiling height below 5 feet is counted

This is why cape cod homes and half-story spaces often have lower square footage than their floor area suggests. The knee-wall areas with low ceiling heights are excluded.

What about lofts, vaulted ceilings, and open floor plans?

Lofts

A loft counts toward GLA if it is finished, above grade, and meets the ceiling height requirements. Open lofts that overlook a living area below are counted for their own floor area, not for the full height of the double-height space below.

Vaulted ceilings

Vaulted ceilings do not add to square footage. A room with a 20-foot vaulted ceiling has the same floor area as an identical room with an 8-foot flat ceiling. Square footage measures floor area, not volume.

Open floor plans

Open floor plans do not change the calculation. The total floor area is measured from the exterior perimeter regardless of whether interior walls are present. An open-plan kitchen, dining, and living area with no dividing walls counts the same as the same space divided into three separate rooms.

Why different sources show different square footage

Tax records, MLS listings, and appraisals often disagree because they use different standards or different measurement dates. County assessors may include finished basements in their square footage figure — and assessor records are often wrong. Listing agents may use the assessor number without knowing it includes below-grade space. The result is that the number shown on Zillow or Redfin is often not the same number an appraiser would calculate. This is also why square footage affects your property taxes — and why disputing an inaccurate assessor record can lower your tax bill.

This discrepancy is why appraisers always measure independently rather than relying on assessor records or listing data. The appraised GLA is the number that matters for lending purposes, regardless of what any other source shows. Listing agents who pass along incorrect figures can face legal consequences — see real estate agent square footage liability for what agents are required to know and disclose.

Rooms that are in a gray zone

In-law suites and ADUs

An in-law suite or ADU that is above grade, finished, and connected (or part of the main structure) may count toward GLA. A detached ADU or guest house is typically measured and valued separately. Local appraiser practice varies, and the specific configuration matters significantly.

Sunrooms and enclosed porches

Whether a sunroom counts depends on how it was built. A room with full exterior walls, HVAC, insulation, and a permit as heated living space is more likely to count than an added-on porch with single-pane glass and no heating. Appraisers exercise judgment, and local market convention matters.

Finished bonus rooms above garages

A finished room above a garage is typically above grade and counts toward GLA if it meets ceiling height requirements and is accessible via standard interior stairs. Some appraisers require it to be heated by the same system as the main house; others accept supplemental heating. This is a common area of variation.

How to verify what counts in your home

If you need a defensible square footage figure, order an independent measurement. A licensed appraiser using ANSI Z765 exterior dimensions is the most reliable option. For a faster self-check, use a to-scale floor plan if one is available: upload it to PlanSnapper, trace the above-grade exterior perimeter only, and set a known reference dimension. The result reflects the same methodology appraisers use, without paying for a full appraisal.

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Frequently Asked Questions

What counts as square footage in a house?

For appraisal purposes, GLA counts above-grade, finished, heated space measured from the exterior walls. Garages, unfinished basements, covered porches, unheated sunrooms, and crawl spaces do not count. Finished attics qualify if they have adequate ceiling height and heat.

Does a garage count toward a home's square footage?

No. An attached garage is not finished living space and is excluded from GLA under ANSI Z765. It is noted separately on the appraisal form and may add value as a site improvement, but it does not count toward the GLA figure used in loan underwriting.

Does a covered porch or deck count toward square footage?

Covered porches, decks, and patios do not count toward GLA. They are exterior improvements and are noted separately. A four-season room that is fully insulated, heated, and finished to the same standard as the interior may qualify as GLA, but open or screened porches do not.

Does a finished attic count as square footage?

A finished attic counts as GLA if it meets ANSI Z765 ceiling height requirements: at least 50% of the finished floor area must have 7-foot ceilings, and no area with ceilings below 5 feet is counted. It must also be heated, cooled, and accessible from the home's interior.

Does a sunroom count as square footage?

Only if the sunroom is heated and cooled by the home's primary HVAC system and accessible from inside the house without going outdoors. An unheated three-season room or screened porch does not count as GLA under ANSI Z765, regardless of how finished it is.

Does square footage include the thickness of walls?

Yes — under ANSI Z765, residential square footage is measured from the exterior faces of the outer walls, which means wall thickness is included in the GLA calculation. This is why appraiser-measured GLA is typically slightly larger than interior room-by-room measurements.

What is the difference between square footage and gross living area?

Gross living area (GLA) is the specific term used on appraisal forms for above-grade finished, heated, and cooled residential space measured under ANSI Z765. Square footage is a general term. When an appraiser reports GLA, they are using the ANSI-compliant definition, which excludes basements, garages, and unfinished space.

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