Square footage of an irregular room — split it into simple shapes and add the areas

You never measure an odd shape directly. Split the room into simple shapes the calculator knows — rectangle, triangle, circle, trapezoid — find each area, and add them. Here an L-shape is 12 × 8 (96 ft²) plus 7 × 6 (42 ft²) = 138 ft².

A plan view of an L-shaped room broken into two rectangles to find its area. Rectangle A is the full-width top section, 12 feet by 8 feet, which is 96 square feet. Rectangle B is the smaller bottom-left section, 7 feet by 6 feet, which is 42 square feet. A dashed line marks the split between them. Added together, 96 plus 42 gives a total of 138 square feet. The method generalizes: a bay or angled wall becomes a triangle (one-half base times height) or a trapezoid, and a rounded area becomes a circle (pi times radius squared) — you split the space into simple shapes, solve each, and sum them. — Source: Plane geometry; SHAPES catalog + add sections from the square-footage calculator

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A plan view of an L-shaped room broken into two rectangles to find its area. Rectangle A is the full-width top section, 12 feet by 8 feet, which is 96 square feet. Rectangle B is the smaller bottom-left section, 7 feet by 6 feet, which is 42 square feet. A dashed line marks the split between them. Added together, 96 plus 42 gives a total of 138 square feet. The method generalizes: a bay or angled wall becomes a triangle (one-half base times height) or a trapezoid, and a rounded area becomes a circle (pi times radius squared) — you split the space into simple shapes, solve each, and sum them.

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    <img src="https://remodelcalculators.com/api/figure-embed/square-footage-shape-breakdown" alt="A plan view of an L-shaped room broken into two rectangles to find its area. Rectangle A is the full-width top section, 12 feet by 8 feet, which is 96 square feet. Rectangle B is the smaller bottom-left section, 7 feet by 6 feet, which is 42 square feet. A dashed line marks the split between them. Added together, 96 plus 42 gives a total of 138 square feet. The method generalizes: a bay or angled wall becomes a triangle (one-half base times height) or a trapezoid, and a rounded area becomes a circle (pi times radius squared) — you split the space into simple shapes, solve each, and sum them." width="800" height="480" style="width:100%;height:auto;border:0" loading="lazy">
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    Diagram: <a href="https://remodelcalculators.com/construction-diagrams/square-footage-shape-breakdown" target="_blank" rel="noopener">Square footage of an irregular room — split it into simple shapes and add the areas</a> — courtesy of <a href="https://remodelcalculators.com" target="_blank" rel="noopener">RemodelCalculators.com</a>
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Read the guide: Measure Room Square Footage