About the Area Converter
This area converter moves between the ten units that turn up on property listings and land records: square millimetres through to square kilometres on the metric side, plus square inches, feet, yards, acres and square miles. Area conversion catches people out because the factors are not the same as the length ones — you have to square them, so a metre being 3.28 feet means a square metre is 10.76 square feet, not 3.28. The tool applies the squared factors for you and lists the same area in every unit underneath the result.
How to use the Area Converter
- 1
Enter the area figure in the Value box.
- 2
Choose the unit it is currently expressed in from the From list.
- 3
Choose the unit you want from the To list.
- 4
Read the converted area, and use the table below to compare across metric and imperial land units at once.
What people use it for
Comparing property listings
A flat advertised at 850 sq ft is 78.97 m². Converting before comparing avoids the illusion that a larger-sounding number means a larger home.
Land, plots and agriculture
A 5 acre plot is 2.023 hectares or 20,234 m². Agricultural yields are usually quoted per hectare while sale listings often use acres.
Ordering flooring or paint
Work out a room in square metres, convert to square feet if the supplier quotes that way, then add ten percent for cuts and wastage.
Why area factors are squared
Area is a two-dimensional measure, so any conversion factor has to be applied twice. A foot is 0.3048 metres, so a square foot is 0.3048 × 0.3048 = 0.09290304 square metres, and one square metre is therefore 10.7639 square feet. The same logic gives 1 square inch as 0.00064516 m², since 0.0254 squared, and 1 square mile as 2,589,988.11 m², since 1,609.344 squared. This is also why scaling a shape behaves counter-intuitively. Double every side of a room and you quadruple its floor area; triple the sides and the area grows ninefold. A pizza that is 40 percent wider has almost double the food. Conversely, an area figure hides a much smaller difference in linear terms: a room 10 percent larger in area is only about 5 percent longer on each side. The step from square metres to square kilometres is a factor of a million rather than a thousand, which is the mistake most often found in land-area arithmetic done by hand.
Acres, hectares and the units of land
The acre is medieval in origin, notionally the area a yoke of oxen could plough in a day, and it survives as exactly 4,840 square yards, which is 43,560 square feet or 4,046.856 square metres. Its awkward shape comes from the furlong-by-chain rectangle it was defined as: 220 yards long by 22 yards wide. Exactly 640 acres make a square mile, which is why the US Public Land Survey System divides townships into square-mile sections, and quarter-quarter sections of 40 acres became the standard homestead parcel. The hectare is the metric alternative and is far cleaner: 10,000 square metres, or a square 100 metres on each side. One hectare is 2.4711 acres, and one acre is 0.4047 hectares. A useful reference is that a full-size football pitch is roughly 0.7 hectares, or about 1.76 acres, of playing surface. Regional units still appear in property records and are worth watching for — the bigha in parts of India, the rai in Thailand, the dunam across the eastern Mediterranean — none of which are standardised nationally and none of which are covered here.
Tips
- Multiply square metres by 10.764 for square feet; the common error is using 3.28, which is the length factor.
- Property listings sometimes quote gross internal area and sometimes usable area, so convert like for like before comparing.
- For an irregular plot, split it into rectangles and triangles, work out each area separately and add them together.