### Square Feet

**Abbreviation/Symbol:**

- sq ft
- ft²
- When describing architecture or real estate, the square foot is often symbolised as a square with a line or slash through it.

**Unit of:**

- Area

**Worldwide use:**

The square foot is used mainly in the United States, Canada and the United Kingdom as a measurement of area.

**Description:**

The square foot is a unit of area used in the imperial and U.S. customary measurement systems.

A square measurement is the two-dimensional derivative of a linear measure, so a square foot is defined as the area of a square with sides 1 ft in length.

**Definition:**

In metric terms a square foot is a square with sides 0.3048 metres in length. One square foot is the equivalent to 0.09290304 square metres.

**Common references:**

- The six floors of the White House (Washington D.C., U.S.A.) have a combined floor-space area of approximately 55,000 square feet.
- In 2003 the average new-build house in the UK had a floor-plan of 818 ft², whereas a new-build house in the United States was on average nearly three times larger, with a floor-plan of 2,300 ft².

**Usage context:**

The square foot is primarily used to indicate area in architecture, real estate and interior space plans.

Square feet can be used to describe the area of any surface such as a floor-plan, wall or roof, whereas acres are used exclusively to describe the area of a parcel of land.

1 square foot = approximately 0.000022959 acres.

1 acre = 43,560 square feet.

To calculate the area of a room in square feet, measure the length and width of the room in feet, then multiply these figures together to give an area in ft².

For example, a room measuring 12 ft x 15 ft would be described as having an area of 180 ft² (12 x 15 = 180).

When using square feet it is important to remember that the figure in square feet refers to the total area of a given space, not the actual dimensions of that space. For example, a room described as being 20 ft² does not measure 20ft x 20ft, (which would in fact be a 400 ft² room). Rather, a room with sides measuring 4ft x 5ft would have an area of 20 ft².

**Component units:**

- 1 ft² can be subdivided into 144 square inches (Sq In – or squares with sides measuring 1 inch).

**Multiples:**

- 1 square yard (Sq Yd) = 9 ft²
- One yard is three feet, so a square yard can be imagined as a square with sides of three feet, or a square block comprising nine individual squares with sides one foot in length.