Square Footage Calculator
By Stephen Morrison, Editor Last reviewed
Add one area for a simple room, or several for L-shapes and odd layouts. Mark an area as a cut-out to subtract things like a kitchen island or a hearth.
Quick answer: square footage = length × width, in feet. A 12 × 14 ft room is 168 sq ft. For an L-shape, split it into two rectangles and add them.
Formulas for each shape
Triangle: base × height ÷ 2
Circle: π × diameter² ÷ 4
Trapezoid: (side 1 + side 2) ÷ 2 × height (sides = the two parallel sides)
Inches: feet + inches ÷ 12
Sq yards: sq ft ÷ 9 Sq meters: sq ft × 0.09290304
How to measure a room
- Measure wall to wall at floor level along the longest straight runs.
- Sketch the room. Split anything that isn't a rectangle into rectangles, triangles or half-circles.
- Add each piece above as its own area. Add closets you'll floor too.
- Subtract things you won't cover, like a kitchen island, by ticking "Cut-out".
- For flooring and tile, add about 10% extra for cuts.
Unit conversions
| From | To | Multiply by |
|---|---|---|
| sq ft | sq yd | ÷ 9 |
| sq ft | sq m | × 0.0929 |
| sq m | sq ft | × 10.764 |
| acres | sq ft | × 43,560 |
| sq in | sq ft | ÷ 144 |
Common questions
How do I calculate the square footage of a room?
Measure the length and width in feet and multiply them. A 12 × 14 ft room is 168 sq ft. If a measurement has inches, enter them in the inches box. 6 inches is half a foot, so 12 ft 6 in is 12.5 ft.
How do I measure an L-shaped room?
Split it into two rectangles that don't overlap, measure each and add them. A 20 × 12 ft space with a 10 × 8 ft nook is 240 + 80 = 320 sq ft. Use "Add another area" above for the second rectangle.
How much extra flooring should I buy?
Most installers add about 10% for cuts and mistakes, and more for diagonal layouts or patterned tile. A 12 × 14 ft room with 10% extra comes to 184.8 sq ft. Check the flooring maker's instructions; some give their own figure.
How do I convert square feet to square yards?
Divide by 9, because a square yard is 3 ft × 3 ft. Carpet is often priced per square yard, so 168 sq ft is 18.67 sq yd.
How many square feet are in an acre?
43,560. A quarter-acre lot is 10,890 sq ft.
Does a house's square footage include the garage?
Usually not in a listing. Appraisers in the US commonly measure "finished" living area and report garages, unfinished basements and porches separately. For a flooring or paint project, just measure the space you are working on.
Sources
Formulas and figures last checked against these sources on. Spotted an error? Tell us and we'll fix it.
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