Square Footage of an L-Shaped or Irregular Room
Draw an L-shaped room, or start from the L shape and type its sizes, and see the floor area of the outline in square feet. The worked example on this page shows each step.
A ready-made setup of the Square Footage Calculator (Square Feet of Any Room or Shape).
Estimates for planning, not professional advice. Read the full notice.
Floor: shape and size
Skip the drawingDrag a round corner to move it. The small hollow diamond on a side is its curve handle: drag it across the side to curve the side (it is not a corner). To add a corner (a new point), tap the side itself, then choose Add a point here. Tapping a corner or a side opens its actions. Drag empty space to move the view; pinch, or Ctrl and the mouse wheel, to zoom. The keys are listed under Keys.
Keys
- Tab
- next corner; each says how far it is from corner 1
- Arrow keys on a corner
- move it one square; ten with Shift; 1/16 in with Alt
- Delete or Backspace
- remove the corner; its two sides join in one straight side
- + on a corner
- add a corner halfway along the next side
- Arrow keys on the drawing
- move the view; farther with Shift
- + and - on the drawing
- zoom in and out
- 0 on the drawing
- show the whole shape
- Ctrl+Z (Cmd+Z on a Mac)
- undo, except inside a typed field (it keeps its own)
- Ctrl+Shift+Z or Ctrl+Y
- redo
- Escape while dragging
- put it back where it was
- Enter on a corner or side
- go to its actions
- Escape in the actions
- close them and go back to the drawing
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- Area
- 320 ft²
- Perimeter
- 80 ft
- Cut-out edges
No area until the shape is fixed.
Estimate for planning, from what you entered and the product data shown. Check product labels and your supplier before you buy.
Shape: L-shape Change
Sides
Corners
Cut-outs
Feet and inches, like 12' 6"
Example sizes
- Overall width
- 20 ft
- Overall length
- 20 ft
- Notch width
- 10 ft
- Notch length
- 8 ft
The result shown is worked out from these sizes.
Example: an L-shaped room
320 ft²
- Same L as one outline 320 ft²
- Walls around it 80 ft
Your project
Enter a size to see your total.
New rooms start at 20 ft × 20 ft (an L shape with a 10 ft × 8 ft notch) until you change them.
Each product is rounded up once for the whole project, so the total can be less than the items bought alone added together. A line counted from a cut layout (sheets, boards or tiles laid out piece by piece) is counted for each item and added.
Worked example: an L-shaped room
Show the working
- Wide part, as a rectangle 20 ft × 12 ft = 240 ft²
- Narrow part, as a rectangle 10 ft × 8 ft = 80 ft²
- Add the two rectangles 240 ft² + 80 ft² = 320 ft²
- The same L as one outline: the whole rectangle less the notch 400 ft² − 80 ft² = 320 ft²
- Walls around the outline 20 ft + 12 ft + 10 ft + 8 ft + 10 ft + 20 ft = 80 ft
Rooms that aren't rectangles
Floor area in square feet, and the length of the walls, for rooms with a bay, a curve or a cut-out
| Room | Floor area, square feet | Walls, feet |
|---|---|---|
| 12 ft × 14 ft room with a bay, as one outline | 180 ft² | 53.66 ft |
| 12 ft × 14 ft room and its bay, as two rooms | 180 ft² | 52 ft |
| Circle 10 ft across | 78.54 ft² | 31.42 ft |
| 10 ft × 4 ft room with a curved side of 8 ft radius | 51.98 ft² | 28.8 ft |
| 12 ft × 12 ft room with a 2 ft × 3 ft cut-out | 138 ft² | 48 ft |
| U-shaped room 14 ft × 12 ft, notch 6 ft × 5 ft | 138 ft² | 62 ft |
| T-shaped room, top 16 ft × 6 ft, stem 6 ft × 10 ft | 156 ft² | 64 ft |
Walls are the room's perimeter. A room drawn as two rooms shows its main room's walls, since the bay opens into it. The curved room's perimeter is its three straight sides and the curved side measured along the arc. A cut-out takes floor away and no wall.
Questions
How do I find the square footage of an L-shaped room?
Split the L into two rectangles, find each one's floor area and add them. Or measure the whole rectangle around the L and take the notch away. Both ways give the same exact total. The worked example on this page shows each way, and the calculator measures the one outline you draw.
How do I measure an irregular or curved room?
Break the room into simple pieces such as rectangles, triangles and trapezoids, add their exact areas and round once at the end. A curved wall is part of a circle, so its length is measured along the arc, not straight across.
What do I do about a kitchen island or a hearth?
Treat it as a cut-out. It takes its own footprint away from the floor you will cover, but it adds no wall, so the length around the room stays the same.
Is a bay or a closet its own room?
Either way works. Enter it as a separate room and add the two floors, or draw the room and the bay as one outline. The total is the same as long as the opening between them is not counted twice. This is the floor you will cover, not the listed size of a home.