Conversion from 10 Square hectometers to Ares

Information about the Square hectometer (hm²)

The square hectometre is a unit of area equal to ten thousand square metres. It is written hm², and it is the area of a square one hundred metres on a side, since a hectometre is one hundred metres. It is exactly one hectare, and the two names describe the same quantity by two different routes.

The routes are worth distinguishing. The hectare is built by putting the prefix hecto in front of the are, so it is a hundred ares. The square hectometre is built by squaring a prefixed length, which is how the International System forms every derived area. The second construction is the strictly coherent one; the first is the one written on every land title in the world.

That difference explains where each name is found. Hectare appears in agriculture, forestry, planning, taxation and international statistics. Square hectometre appears mainly in technical and cartographic work in Spanish-speaking countries, where the hectometre is a familiar prefixed length for other reasons, and in documents where an author has chosen to keep every unit inside strict SI form.

The related cubic form is genuinely common in one field. Spanish and Latin American hydrology reports reservoir capacity and river flow in cubic hectometres, a cubic hectometre being one million cubic metres, so a reservoir holding 500 hm³ is holding half a cubic kilometre of water. Readers used to seeing hm in that context find hm² unremarkable, which is much of why the form survives there and almost nowhere else.

For scale, ten thousand square metres is a square one hundred metres on a side. That is about one and a half association football pitches, a large city block, or a good-sized field. It is the largest area that can still be walked around comfortably in a couple of minutes, and it is where land measurement stops being architectural and starts being agricultural.

When converting, the two names need no arithmetic between them: one square hectometre is one hectare exactly. Going further, multiply by ten thousand for square metres or divide by a hundred for square kilometres, and remember that the imperial comparison, 2.471 acres, is the same for both names.

One square hectometre equals 10,000 square metres, 1 hectare, 0.01 square kilometres, or about 2.471 acres.

Information about the Are (a)

The are is a unit of area equal to one hundred square metres, written a. It is a square ten metres on a side. It was created by the French metric legislation of 1795 as the basic decimal unit of land, taking its name from the Latin word for a level open space, and it is the parent of the hectare that eventually overshadowed it.

The original scheme was tidy. The are would measure a garden or a plot, the hectare a field, and the centiare a single square metre, giving three decimal steps that covered everything from a doorway to a farm. In practice the middle rung carried almost all the weight: fields were described in hectares and buildings in square metres, and the are was left with the narrow band between.

It nevertheless survives in land registration, and there it is entirely alive. French, Belgian and Luxembourgish deeds record parcels as hectares, ares and centiares in three columns, so a plot might be written as 1 ha 25 a 30 ca, meaning 12,530 square metres. In Poland the ar is the ordinary way of describing a building plot, and in Indonesia and parts of central Europe it fills the same role.

For scale, one are is a square ten metres on a side: a generous garden, a small yard, or the footprint of a modest house with a little room to spare. A badminton court is a little over eight tenths of an are, a single-car garage about one fifth, and a tennis court about two and a half. It is the largest unit that still describes something a person can pace out in a few seconds.

In strict SI terms the are is exactly the square decametre, since a decametre is ten metres. The two are the same quantity written two ways, and the SI form is essentially never used, which makes the are one of the few cases where the older unit is the readable one.

Its main practical trap is the symbol. A single lower-case a is easily lost in running text or mistaken for an abbreviation, which is why deeds usually write it in a fixed column and why anything ambiguous is safer converted to square metres before it is passed on.

One are equals 100 square metres, 0.01 hectares, or about 1076.4 square feet.