# What is the square footage?

Computes the area of a rectangle, circle, triangle or trapezoid, times how many, in square feet, square yards and square metres, with an optional cost.

- Page: https://www.acalculator.org/construction/square-footage-calculator
- JSON spec: https://www.acalculator.org/construction/square-footage-calculator.json
- Version: 1d82824286b1

## Default answer

Example with the default inputs (Shape Rectangle or square, Length 12 ft, Width 14 ft, How many 1, Price per Square foot): The area is 168 ft².

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| shape | Shape | The shape of the area. |
| len | Length | The length of the rectangle. |
| wid | Width | The width of the rectangle. |
| dia | Diameter | The diameter of the circle. |
| base | Base | The base of the triangle. |
| h | Height | The height of the triangle or trapezoid, measured at right angles to the base. |
| a | Top side | The first of the two parallel sides of the trapezoid. |
| b | Bottom side | The second of the two parallel sides of the trapezoid. |
| qty | How many | How many areas of this size. |
| price | Price | The price per square foot, square yard or square metre. Leave empty to skip the cost. |
| per | Price per | The area unit the price is for. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| squareFeet | Area | The total area in square feet. |
| squareYards | Square yards | The total area in square yards (9 square feet each). |
| squareMeters | Square metres | The total area in square metres. |
| cost | Cost | The total area in the price unit × the price. |

## Method

area = area of the shape × how many; square yards = square feet ÷ 9

## Assumptions

- Rectangle: length × width. Circle: π × diameter² ÷ 4. Triangle: base × height ÷ 2. Trapezoid: (top + bottom) ÷ 2 × height.
- The area is the flat floor area. It adds nothing for waste or pattern matching.
- The cost is the area in the price unit × the price.

## Worked examples

1. shape = rectangle, len = 3.6576, wid = 4.2672, qty = 1, per = ft2, price = $3.50 gives squareFeet = 15.607711, cost = $588.00. Source: hand calculation in content.mdx: 12 × 14 = 168 ft²; × $3.50 = $588.
2. shape = circle, dia = 3.048, qty = 1, per = ft2 gives squareFeet = 7.296588. Source: hand calculation in content.mdx: π × 10² ÷ 4 = 78.54 ft².
3. shape = triangle, base = 3.048, h = 2.4384, qty = 2, per = ft2 gives squareFeet = 7.432243. Source: hand calculation in content.mdx: 10 × 8 ÷ 2 = 40 ft²; × 2 = 80 ft².
4. shape = trapezoid, a = 1.8288, b = 3.048, h = 2.7432, qty = 1, per = yd2, price = $30.00 gives squareFeet = 6.689019, squareYards = 6.689019, cost = $240.00. Source: hand calculation in content.mdx: (6 + 10) ÷ 2 × 9 = 72 ft² = 8 yd²; × $30 = $240.

## FAQ

### How do I calculate square footage?

For a rectangle, multiply the length by the width, both in feet. A room 12 ft by 14 ft is 12 × 14 = 168 square feet.

### How do I find the square footage of an L-shaped room?

Split the room into rectangles, work out each one, and add them. A 12 × 14 room with a 4 × 6 nook is 168 + 24 = 192 square feet.

### How many square feet are in a square yard?

Nine. A yard is 3 feet, so a square yard is 3 × 3 = 9 square feet. Carpet is often priced per square yard: divide square feet by 9.

### How do I convert square feet to square metres?

Multiply by 0.09290304. A foot is exactly 0.3048 m, so a square foot is 0.3048² = 0.09290304 m². 168 square feet is 15.61 m².

### What if my measurements are in inches?

Type them with the unit, such as 150 in, or pick inches in the unit list. The calculator converts every size before it multiplies.

### Should I buy extra flooring?

The area here is the exact floor area with nothing added. Flooring is cut to fit at the walls and patterns must line up, so buy extra; the product’s installation guide says how much.

## Sources

- NIST SP 811 (2008), Appendix B: 1 ft = 0.3048 m exactly, so 1 ft² = 0.09290304 m²; 1 yd = 3 ft.