Room Square Footage Calculator

Measure the floor in square feet — a simple rectangle, or an L-shaped room split into two rectangles you add together. This is the number every flooring estimate starts from.

Confirm coverage against your product’s box/spec sheet and buy 5–10% extra for cuts, waste and future repairs. Coverage and box sizes vary by brand.

Calculator

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For a simple rectangular room, set the second rectangle to 0.
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Total floor area260 sq ft
Rectangle 1 (L × W)180 sq ft (12 × 15)
Rectangle 2 (L × W)80 sq ft (8 × 10)

Splitting the room into rectangles — 180 sq ft plus 80 sq ft — gives about 260 sq ft. For an L-shaped room, measure each rectangle and add them; set the second rectangle to 0 for a simple room. Then add your waste factor before buying.

Every flooring order begins with one honest measurement: the floor area in square feet. This calculator keeps it simple by letting you break the room into up to two rectangles — which covers a plain rectangular room and the most common L-shaped and bumped-out layouts. Measure each rectangle in feet, and the tool multiplies and adds them for you.

For a simple room, enter the length and width of the first rectangle and leave the second at 0. For an L-shape, draw the room on paper, slice it into two clean rectangles, measure each, and enter both. Odd nooks, closets and bay windows are just more small rectangles — measure and add them the same way.

Formula

area = (len1 × wid1) + (len2 × wid2)

Floor area is just length × width for each rectangle, summed. Work in feet and the result is in square feet directly. Set the second rectangle to zero for a single-rectangle room. To convert to square yards for carpet, divide by 9 (see the carpet calculator).

Worked example

An L-shaped room made of a 12 × 15 ft main area and an 8 × 10 ft extension:

  • Rectangle 1 = 12 × 15 = 180 sq ft
  • Rectangle 2 = 8 × 10 = 80 sq ft
  • Total = 180 + 80 = 260 sq ft

That 260 sq ft is the raw floor area — before waste. Add your waste factor next: at 10% you’d order about 286 sq ft of material. Carry the total straight into the flooring calculator to turn it into boxes.

Measuring tips for an accurate count

Measure at floor level, wall to wall, and round each dimension to the nearest inch (a tape reads in inches; 6 in = 0.5 ft). Measure the widest points and ignore baseboards — the flooring runs to the wall behind them. Do not subtract small obstacles like a kitchen island or a hearth unless they are large; the flooring under and around them still gets cut from your boxes, and the extra becomes part of your waste allowance.

Once you have the area, decide the waste factor with the waste-factor helper, then size tile with the tile calculator. This tool is a pure geometry helper — it never adds waste on its own, so the number you see is the true floor area.

Frequently asked questions

How do I calculate square footage of a room?
Multiply the room’s length by its width in feet. For an L-shaped room, split it into two rectangles, find each area and add them. A 12 × 15 ft plus 8 × 10 ft room is 180 + 80 = 260 sq ft.
How do I measure an L-shaped room?
Divide the L into two rectangles along a straight line, measure the length and width of each, and enter both here. The calculator multiplies and adds them into a single total.
Should I subtract cabinets, islands or a fireplace?
For most rooms, no — leave the full area and let the waste factor absorb it. Only subtract a genuinely large permanent feature (like a big kitchen island) by treating it as a rectangle to remove.
How many square feet is a 12x12 room?
A 12 × 12 ft room is 144 sq ft. Enter 12 and 12 for the first rectangle and 0 for the second; then add a waste factor before ordering flooring.
How do I convert square feet to square yards?
Divide square feet by 9, since 9 sq ft = 1 sq yard. Carpet is often sold by the square yard — the carpet calculator handles the conversion and the waste factor.