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How to measure an L-shaped room

Break an L-shaped room into simple rectangles, add the areas and subtract any missing cut-outs.

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Quick answer

Break an L-shaped room into simple rectangles, add the areas and subtract any missing cut-outs.

How to do it

  1. Sketch the room and split it into rectangles.
  2. Measure length × width for each rectangle.
  3. Add the rectangle areas together.
  4. Subtract any fixed cut-outs you do not need to cover.

Worked example

A 4 m × 3 m room is 12 m². Add a 1 m × 0.8 m alcove and subtract a 0.6 m × 0.4 m hearth to get 12.56 m².

Common mistakes

  • Forgetting alcoves and bay windows.
  • Counting fixed cut-outs that flooring or tiles will not cover.
  • Mixing centimetres and metres.

When this is not suitable

Do not treat any quick estimate as a final specification where safety, contracts, regulations or expensive purchases depend on it.

Related next tools

Next useful tools for this room or material estimate.

HomePaint CalculatorCalculate paint from a known area, imported area or by measuring walls, doors, windows and ceilings. HomeFlooring CalculatorEstimate floor area, waste and packs with extra rectangles and removed areas built in. HomeTile CalculatorWork out tile quantities from area, tile size and waste allowance. HomeWallpaper CalculatorEstimate wallpaper rolls from wall area, roll size and waste allowance.

Keep the result together

Use the calculator first, then add the result to a Project Sheet if you need a clean printable summary.

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