Area Converter
Convert an area between metric units (square kilometres, hectares, square metres, square centimetres) and the units used for land and floor space in the United States and the United Kingdom: acres, square miles, square yards, square feet and square inches.
Result
Enter a value to convert.
The calculation runs in this browser tab. Nothing you enter is uploaded, saved or logged.
How are units of area defined?
Area is a length squared, so every area unit is the square of a length unit. A square metre is a square one metre on a side, and because there are 100 centimetres in a metre, a square metre contains 100 × 100 = 10,000 square centimetres, not 100. This is the most common source of mistakes when converting by hand.
Some area units have their own names. The hectare is exactly 10,000 square metres (a square of 100 m by 100 m) and is the standard unit for farmland. The acre, 43,560 square feet, is defined through the international foot and equals exactly 4,046.8564224 square metres, or about 0.4047 hectare. A square mile contains exactly 640 acres.
How to use the Area Converter
- Enter the area you want to convert. Negative values are not accepted.
- Choose the unit you are converting from and the unit you are converting to.
- Read the result, the conversion factor and the inverse factor. A leading ≈ means the value was rounded to the selected precision.
- Use the table to see the area in every unit, and Copy result to copy the number alone.
Formula
- General rule
- result = value × (m² per source unit) ÷ (m² per target unit)
- Acres to hectares
- ha = acres × 0.40468564224
- Square feet to square metres
- m² = ft² × 0.09290304
- Square metres to square feet
- ft² = m² ÷ 0.09290304 ≈ m² × 10.7639
A square unit is the square of the length factor: 1 ft = 0.3048 m, so 1 ft² = 0.3048² = 0.09290304 m². That is why the area factor is not the length factor.
Equivalents: 1 km² = 100 ha; 1 mi² = 640 ac; 1 ac = 4,840 yd² = 43,560 ft²; 1 yd² = 9 ft²; 1 ft² = 144 in².
Worked example
A plot of 2.5 acres in hectares. These are the results the converter gives:
| Question | Result |
|---|---|
| Input: Value | 2.5 |
| Input: From | Acres (ac) |
| Input: To | Hectares (ha) |
| Input: Precision | 10 significant digits |
| 2.5 ac equals | ≈ 1.011714106 ha |
| Conversion factor | 1 ac = ≈ 0.4046856422 ha |
| Inverse | 1 ha = ≈ 2.471053815 ac |
| Formula | ha = ac × 0.40468564224 |
Assumptions and limits
- The acre is the international acre, based on the international foot. The US survey acre differs by about two parts per million, which only matters in land surveying.
- The converter changes the unit of an area. It does not compute an area from dimensions: multiply length by width first, in the same unit.
- Results are shown to 6 to 15 significant digits. Non-terminating conversions, for example hectares to acres, are rounded and marked ≈.
- Local units such as the dunam, bigha or tsubo are not included, because their size varies by region.
Frequently asked questions
How many square feet are in an acre?
Exactly 43,560. An acre was historically the area a team of oxen could plough in a day, a strip of one chain (66 ft) by one furlong (660 ft), which is 43,560 square feet.
How many hectares are in an acre?
One acre is about 0.404686 hectare. In the other direction, one hectare is about 2.471054 acres.
How many square metres are in a hectare?
10,000. A hectare is a square of 100 metres by 100 metres, and 100 hectares make one square kilometre.
How do I convert square feet to square metres?
Multiply by 0.09290304. A 1,200 ft² apartment is 111.48 m². A quick approximation is to divide the square feet by 10.76.
Why isn’t 1 square metre equal to 100 square centimetres?
Because area scales with the square of the length. One metre is 100 cm, so one square metre is 100 cm × 100 cm = 10,000 cm². The same applies to every area conversion.
How many acres are in a square mile?
Exactly 640, which is also 258.9988 hectares.