Square Footage Calculator
Add up multi-shape rooms — a rectangle plus a bumped-out alcove, or an L-shape made of two rectangles. Sums automatically as you type.
Total area
Sum of all sections
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Square meters
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Sections
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Per section
Real rooms aren't rectangles
Bay windows, alcoves, angled walls, peninsulas — most "rectangular" rooms have at least one feature that breaks the rectangle. Measure the simplest decomposition: a big rectangle, plus the bump, minus the cutout. Add them up.
The formulas
- Rectangle: length × width
- Triangle: ½ × base × height
- Circle: π × (diameter / 2)²
- Trapezoid: ½ × (top + bottom) × height
Common gotchas
- Measure to the inside of the walls if you're flooring; to the outside if you're siding.
- Closets count — they need flooring too.
- Stairs aren't square footage; they're treated separately by most trades.