Square footage calculator
Add up the square footage of a room, a floor or a whole house, and see which part counts as gross living area (GLA) under the ANSI Z765 standard.
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How square footage is worked out
Each room's area is its length times its width, and the rooms are added together. Irregular rooms can be split into rectangles, each added as its own row.
ANSI Z765, the American standard for measuring single-family homes, counts only finished, above-grade space as gross living area (GLA). Garages, unfinished areas, covered porches and below-grade space are reported separately, even when the basement is finished. Mark each row with its category and the calculator totals each one and shows the GLA on its own.
Room-by-room areas are an approximation: the standard measures the exterior of the house, includes stairs and hallways, and has rules for ceiling height and rounding. For a listing or an appraisal, measure the whole house or use a report built for it.
vPlan AR's square-footage report uses the same categories for a scanned or drawn plan, takes off open-to-below areas, and prints a room-by-room breakdown.
Tips
- Include hallways, stairs and closets on each floor, or the total will be low.
- Measure inside the walls for flooring; appraisers measure the outside of the house for GLA.
- A finished basement is never GLA under ANSI Z765, even with a walk-out.
- Rooms with ceilings under 7 feet are treated differently by the standard; check before counting them.
Do this from a scan instead
Scan the house or draw it, mark each room's category, and vPlan AR produces an ANSI Z765-style square-footage report with the GLA, the other categories and every room's area.
Frequently asked questions
How do I calculate the square footage of a house?
Measure each room's length and width, multiply them, and add the rooms together, including hallways, stairs and closets. Split irregular rooms into rectangles. For the official figure, the ANSI Z765 standard measures the outside of the house, floor by floor.
What counts as gross living area?
Under ANSI Z765, gross living area is finished space above grade that is suitable for year-round use. Garages, unfinished space, covered porches and below-grade rooms (even finished basements) are reported separately and are not part of GLA.
Does a finished basement count as square footage?
It counts toward the total finished area, but not toward gross living area under ANSI Z765, which only counts above-grade space. The calculator shows it as its own category.
Is a garage included in square footage?
No. A garage is reported separately and is not part of the living area, even when it is attached or finished.
Guides
- How to Create an ANSI Z765 Square Footage (GLA) Report for a ListingMeasure gross living area the right way. Scan the home, classify each space, and export a clean square-footage report that separates GLA from garage, basement, and unfinished areas.
- How Real Estate Agents Use LiDAR Floor Plans to Sell Listings FasterA floor plan attached to an MLS listing measurably increases buyer engagement. Here's how agents are capturing them in minutes with an iPhone — no measuring service required.