Square footage calculator
This square footage calculator adds up any mix of rectangles, L-shaped rooms, circles and triangles, and gives the total in square feet, square yards and square meters.
- Add as many areas as you need
- L-shapes, circles and triangles built in
- Optional cost per square foot
Last updated
How to use the square footage calculator
- Measure each space in feet. For inches, divide by 12: 6 inches is 0.5 ft.
- Pick a shape for each area. Split an odd-shaped room into rectangles, or use the L-shape option for two rectangles at once.
- Use “Add an area” for more rooms or sections. Each row shows its own square footage.
- Read the total in square feet, square yards (carpet, sod) and square meters. Add a price per square foot to see the cost.
Square footage formulas
Square footage is an area: how many 1 ft × 1 ft squares fit on the surface. Every shape comes down to one of these:
rectangle = length × width
circle = π × (diameter ÷ 2)²
triangle = base × height ÷ 2
L-shape = (length A × width A) + (length B × width B)
For an L-shape, draw a line that cuts it into two rectangles that do not overlap, then add them. To convert, divide square feet by 9 for square yards, or multiply by 0.092903 for square meters.
Worked example
A 12 × 14 ft living room plus an L-shaped kitchen made of a 10 × 12 ft part and a 4 × 6 ft part.
- Living room: 12 × 14 = 168 sq ft.
- Kitchen: (10 × 12) + (4 × 6) = 120 + 24 = 144 sq ft.
- Total: 168 + 144 = 312 sq ft.
- Square yards: 312 ÷ 9 = 34.67. Square meters: 312 × 0.092903 = 28.99.
For flooring, buy 5 to 10 percent more than the area to cover cuts and mistakes: about 328 to 344 sq ft here.
Common room sizes in square feet
| Size | Sq ft | Sq yd | Sq m |
|---|---|---|---|
| 10 × 10 ft | 100 | 11.11 | 9.29 |
| 10 × 12 ft | 120 | 13.33 | 11.15 |
| 12 × 12 ft | 144 | 16 | 13.38 |
| 12 × 16 ft | 192 | 21.33 | 17.84 |
| 20 × 20 ft | 400 | 44.44 | 37.16 |
| 24 × 24 ft | 576 | 64 | 53.51 |
Measuring tips
- Measure wall to wall at floor level, and round up to the next inch.
- Walls are area too. For paint or siding, multiply the wall’s length by its height, then subtract doors and windows.
- Leave out what you will not cover. For flooring, skip areas under built-in cabinets; for a patio, subtract planting beds.
- Going to concrete or mulch? Carry the total into the concrete calculator or mulch calculator and add a depth.
Common questions
How do I calculate square feet of a room?
Multiply the length by the width in feet. A room 11 ft 6 in by 14 ft is 11.5 × 14 = 161 square feet. For an L-shaped room, split it into two rectangles and add them.
How many square feet is a 12x12 room?
144 square feet. That is 16 square yards, or about 13.38 square meters.
How do I calculate square feet with height?
Height only matters for walls. Multiply each wall’s length by the ceiling height and add them up. A 12 × 14 ft room with 8 ft ceilings has (12 + 14 + 12 + 14) × 8 = 416 sq ft of wall before doors and windows. Length × width × height gives cubic feet, which is volume, not area.
How do I work out the cost per square foot?
Multiply the area by the price per square foot. 312 sq ft of flooring at $3.50 a square foot is $1,092. To find a price per square foot from a quote, divide the total by the square footage.
How do I convert square feet to square yards?
Divide by 9, because a square yard is 3 ft × 3 ft. 450 square feet is 50 square yards.
How do I find the square footage of a circle?
Halve the diameter to get the radius, square it and multiply by 3.1416. A circle 12 ft across is 3.1416 × 6 × 6 = 113.1 square feet.
Sources
- NIST Guide to the SI, Appendix B.9 conversion factors. 1 square foot = 0.092 903 04 square meter (exact)
See the methodology page for how YardageHQ builds and checks its calculators.