Square Footage Calculator
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Result
Square footage
- In square metres
- 17.84 m²
- In square yards
- 21.33 sq yd
- In acres
- 0.0044 acres
The same area in other units
| Unit | Area |
|---|---|
| Square feet (sq ft) | 192 |
| Square inches (sq in) | 27,648 |
| Square yards (sq yd) | 21.33 |
| Square metres (m²) | 17.84 |
| Acres | 0.0044 |
| Hectares | 0.00178 |
How do you calculate square footage?
To calculate square footage, multiply the length in feet by the width in feet. A room 16 feet by 12 feet is 192 square feet. For an L-shaped space, split it into two rectangles, work out each area separately, and add them together.
rectangle: A = l × w circle: A = π(d/2)² triangle: A = ½ b × h trapezoid: A = ½(a + b) × h- l, w
- Length and width in feet
- d
- Diameter in feet, for a circle
- b, h
- Base and perpendicular height, for a triangle
- a, b
- The two parallel sides of a trapezoid
Square footage is length times width, and almost every error on this topic is a shape problem rather than an arithmetic one. An L-shaped room measured as a single bounding rectangle includes the corner that is not there, which over-orders flooring by a fifth or more; split it into two rectangles instead and add them. A circular area needs the diameter halved before squaring, so entering a radius where a diameter belongs understates the area fourfold. A triangle is half of the rectangle that contains it, and the height must be perpendicular to the base rather than measured along a sloping side. For material ordering, note that square footage is the wrong unit for anything sold by volume: flooring and tile are bought by the square foot, but mulch, gravel and concrete are bought by the cubic yard, which needs a depth as well.
- Measure the length and width of the space in feet.
- Multiply length by width for a rectangle.
- Split an irregular space into rectangles and add the areas.
- For a circle, halve the diameter, square it, multiply by pi.
- Add a waste allowance if you are ordering flooring or tile.
Worked example: An L-shaped living room: a 16 × 12 ft main area plus an 8 × 6 ft alcove
An L-shaped living room: a 16 × 12 ft main area plus an 8 × 6 ft alcove
Split the L into two rectangles. The main area is 16 × 12 = 192 square feet. The alcove is 8 × 6 = 48 square feet. Added together that is 240 square feet. The error worth avoiding is measuring the whole footprint as a single rectangle: the bounding box here would be 24 × 12 = 288 square feet, which is 48 square feet of floor that does not exist — a 20% over-order. In other units, 240 square feet is 26.67 square yards, 22.30 square metres, or 0.0055 acres. If you were ordering flooring at $4.50 a square foot with a 10% waste allowance, that is 264 square feet and $1,188. Note that square footage alone will not order mulch or concrete, which are sold by the cubic yard and need a depth as well.
What each square footage input means
- Shape
- The shape of the space. An L-shaped room is treated as two rectangles, which is the correct way to measure it.
- Length
- The longer side in feet. For a triangle this is the base; for a trapezoid, the first parallel side.
- Width
- The shorter side in feet. For a triangle this is the perpendicular height; for a trapezoid, the distance between the parallel sides.
- Second length
- For an L-shape, the length of the second rectangle. For a trapezoid, the second parallel side.
- Second width
- For an L-shape, the width of the second rectangle.
- Diameter
- For a circle, the full width across in feet — not the radius.
- How many identical spaces?
- Multiply the result, for several identical rooms or panels.
- Waste allowance
- Add an allowance if you are ordering flooring or tile. Ten percent is typical for a straight layout, fifteen for diagonal.
- Price per square foot
- Optional. Enter a material price to get a total cost.
What this square footage does not account for
- An L-shape or any irregular room must be split into rectangles. Measuring the bounding box includes space that is not there and over-orders materials.
- Circles take the diameter, not the radius. Confusing the two understates the area by a factor of four.
- A triangle's height must be perpendicular to its base, not measured along a sloping edge.
- Square footage cannot order material sold by volume. Mulch, gravel, topsoil and concrete are bought by the cubic yard and need a depth.
- Closets, alcoves, bay windows and stair openings are routinely forgotten. Measure what the material has to cover, not the nominal room size.
- Gross and net floor area differ. Interior wall thickness means the sum of room areas is less than the building's footprint, which matters for real-estate figures.
Frequently asked questions
How do you calculate square footage of a room?
Multiply the length in feet by the width in feet. A 16 by 12 foot room is 192 square feet. For an irregular room, split it into rectangles, calculate each one, and add the results together.
How do you find square footage of an L-shaped room?
Divide it into two rectangles and add their areas. A 16 by 12 area plus an 8 by 6 alcove is 192 + 48 = 240 square feet. Measuring the bounding box instead over-orders by about 20%.
How many square feet are in a square yard?
Nine, because a yard is three feet and three squared is nine. So 240 square feet is 26.67 square yards. Carpet is often priced per square yard, which is why the conversion matters.
How do you convert square feet to square metres?
Multiply by 0.0929. The factor is exact, since a foot is exactly 0.3048 metres and 0.3048 squared is 0.09290304. So 240 square feet is 22.30 square metres.
How many square feet are in an acre?
Exactly 43,560. That makes a 240 square foot room about 0.0055 acres. The figure comes from an acre being one chain by one furlong in old English land measurement.
How much extra should I order for waste?
Ten percent for a straight tile or plank layout, fifteen for diagonal or herringbone, and more for a room with many cuts. Flooring sold by the box also forces you up to whole boxes.
Sources and review
Last reviewed .