Square Footage Calculator

Last Updated:

Calculate room area in square feet or square meters. Instantly converts between sq ft and sq m.

120 sq ft

= 11.1 sq m

📐 Formula

Area = Length × Width. Sq ft to sq m: multiply by 0.092903. Sq m to sq ft: multiply by 10.7639

How to Use the Square Footage Calculator

1

Select room shape

Choose rectangle (most rooms), triangle, circle, or L-shape. Irregular rooms can be broken into multiple simple shapes and added together.

2

Enter dimensions

Input length and width in feet or metres. For an L-shaped room, the calculator requires the outer dimensions and the dimensions of the rectangular section to subtract.

3

Add all rooms

Use the multi-room feature to calculate each room separately and sum to total home square footage. Label each room for reference.

4

Convert units if needed

Toggle between square feet, square metres, and square yards. The calculator converts automatically — useful when comparing US listings (sq ft) to international properties (sq m).

What Counts as Square Footage?

Square footage measurement standards are not uniformly regulated in the United States, which causes significant confusion. The American National Standards Institute (ANSI) provides guidelines (ANSI Z765) used by most appraisers: finished, above-grade living area is what counts for official square footage. This includes bedrooms, living rooms, kitchen, dining room, bathrooms, hallways, and finished bonus rooms — but only if they meet ceiling height requirements (generally 7 feet minimum).

What typically does not count in standard square footage: unfinished basements (even if used regularly), garages, attics (unless finished and accessible by a permanent staircase), covered porches and patios, and crawl spaces. Some listings include these spaces in a "total area" figure separate from living area — always clarify which is quoted. A 2,400 sq ft listing that includes an unfinished basement may have only 1,800 sq ft of actual living space.

Measuring Your Own Rooms Accurately

Use a laser distance measurer (available for $25–$50) for speed and accuracy over a tape measure. Measure each room at its widest points from wall to wall, including any alcoves or bump-outs. For irregular rooms, sketch the room on paper, divide it into rectangles, calculate each rectangle, and sum them. Bay windows typically add to the interior square footage; exterior protrusions like columns do not. Closets are included in room area. Stairways count at the floor level only.

Square Footage and Property Value

Appraisers and real estate agents use price per square foot as a primary valuation benchmark: divide the sale price by the finished square footage to get the rate, then apply it to the subject property. In practice, the rate is not uniform across a home — primary bedrooms and main living areas carry higher value per square foot than storage rooms or utility spaces. Additions and conversions (garage-to-bedroom, basement finishing) increase square footage but may not increase value proportionally if the quality of finish or ceiling height is below grade for the neighbourhood.

How to Calculate Square Footage by Hand: Worked Example

Measure a rectangular room at 14 ft × 16.5 ft: area = 14 × 16.5 = 231 sq ft. For a home with three main rooms — 14×16.5, 12×11, and 10×9.5 — total area = 231 + 132 + 95 = 458 sq ft for those rooms combined.

Why doesn't a closet count toward Gross Living Area?

Standard appraisal measurement practice (ANSI Z765 in the US) generally counts finished, heated living space, but definitions of what's included can vary by region and appraiser convention. A 3×4 ft closet (12 sq ft) inside one of the rooms above is typically already included as part of that room's footprint if it's within the room's exterior wall measurements — the distinction that actually matters is between finished, climate-controlled space (counted) and unfinished space like an unheated garage, an unfinished basement, or a screened porch (commonly excluded or counted separately from the primary living area figure).

Why Do Two Listings for the Same House Show Different Square Footage?

What's the most common source of discrepancy?

Public tax records, appraiser measurements, and agent-provided listing figures frequently disagree because they're compiled at different times, by different methods, and sometimes include or exclude finished basements and additions inconsistently. A finished basement is a common source of large discrepancies — some measurement standards include it in total square footage, others report it as "below grade" square footage separately, which can make an identical house look meaningfully larger or smaller depending on which figure is quoted.

How should you measure your own rooms accurately?

Measure wall to wall at floor level (baseboards, not door casings), rounding to the nearest inch, and always measure the longer dimension of any irregular room in segments rather than estimating. For L-shaped rooms, split the space into two or more rectangles, calculate each separately, and sum the results — attempting to average an irregular shape into one rectangle reliably overstates or understates the true area.

Does more square footage always mean more property value?

Generally yes within a given neighborhood, but not linearly and not independent of layout. Appraisers and buyers alike often value well-laid-out square footage (usable rooms, good flow) more highly than the same total area split into awkward or cramped spaces — which is why price-per-square-foot comparisons work best between genuinely similar homes, not across very different floor plans in the same size range.

Frequently Asked Questions

Measure the length and width of the room in feet, then multiply the two numbers. For irregular rooms, divide them into rectangles, calculate each area, and add them together.
1 square meter = 10.7639 square feet. 1 square foot = 0.092903 square meters. So a 100 sq ft room is about 9.29 sq m.
1 acre = 43,560 square feet, or approximately 4,047 square meters. A typical suburban house lot is 0.25–0.5 acres (10,890–21,780 sq ft).
Measure each room's length × width in feet. Add all rooms together. For irregular shapes, break into rectangles and add. Include all finished interior areas: bedrooms, living room, kitchen, finished basement. Exclude: unfinished basement, garage, attic (unless finished), covered porches. A measuring tape or laser measure gives the most accurate results.
No. Standard US real estate square footage (GLA — Gross Living Area) excludes garages, unfinished basements, covered patios, and any space that is not heated, finished, and livable. Finished basements are a gray area — some appraisers include them, some list them separately. Always ask how square footage was measured when comparing listings.

Sources & Methodology

Calculations are based on the most current publicly available data from authoritative government and industry sources: