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Area Converter
Area Converter
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How area conversion works, and the squaring trap
Area factors are the square of the corresponding length factors, and forgetting that is the most common area conversion mistake there is. A foot is 0.3048 metres, so a square foot is 0.3048² = 0.09290304 square metres, not 0.3048. Dividing a square-foot figure by 3.28 instead of 10.76 overstates the metric area by more than three times.
The same squaring applies to scaling. Doubling every linear dimension of a room quadruples its floor area, and a 50% increase in length is a 125% increase in area.
Formulas
Square feet to square metres
m² = ft² × 0.09290304
That is 0.3048², not 0.3048.
Square metres to square feet
ft² = m² × 10.7639
Acres to hectares
ha = acre × 0.404686
Worked examples
| From | To | Result |
|---|---|---|
| 1 ft² | m² | 0.092903 m² |
| 1,000 ft² | m² | 92.903 m² |
| 100 m² | ft² | 1,076.39 ft² |
| 1 acre | m² | 4,046.86 m² |
| 1 hectare | acre | 2.47105 acre |
| 1 mi² | km² | 2.58999 km² |
Results are computed with the same factors the converter above uses, rounded to six significant figures.
Common areas
| m² | ft² | acre |
|---|---|---|
| 10 | 107.639 | 0.00247105 |
| 50 | 538.196 | 0.0123553 |
| 100 | 1,076.39 | 0.0247105 |
| 500 | 5,381.96 | 0.123553 |
| 1,000 | 10,763.9 | 0.247105 |
| 4,046.86 | 43,560 | 1 |
| 10,000 | 107,639 | 2.47105 |
The last two rows are exactly one acre and exactly one hectare.
Worth knowing
- 1 in² = 645.16 mm² exactly, because 25.4² = 645.16.
- 1 acre = 4,046.856 422 4 m² exactly. It was historically the area a yoke of oxen could plough in a day, and is defined as 1 chain by 1 furlong, or 66 by 660 feet.
- 1 hectare = 10,000 m² exactly, which is a square 100 m on a side. It is about 2.47 acres.
- A square mile is 640 acres, which is why US public land survey sections are 640 acres, one square mile each.
Frequently asked questions
- Why is a square foot not 0.3048 square metres?
- Because area scales as the square of the linear factor. A square foot is a square 0.3048 metres on each side, so its area is 0.3048 × 0.3048 = 0.09290304 square metres. Using the linear factor by mistake overstates the result by a factor of 3.28.
- How many square feet are in a square metre?
- 10.7639. The reciprocal, 0.0929, converts the other way. Property listings that quote both figures for the same unit are a good place to spot a squaring error.
- What is the difference between an acre and a hectare?
- A hectare is a metric unit of exactly 10,000 square metres, a square 100 metres on a side. An acre is an imperial unit of 4,046.86 square metres, defined as a strip one chain by one furlong. One hectare is about 2.47 acres.
- If I double the size of a room, how much does the area increase?
- It quadruples, if you double both dimensions. Area grows as the square of any linear scaling, so a 2× increase in length and width is a 4× increase in area, and a 50% increase in each dimension is a 125% increase in area.