| Square hands (sq hh) | Square yards (sq yd) |
|---|---|
| 1 Square hand | 0.0123456790123 sq yd |
| 2 Square hands | 0.0246913580247 sq yd |
| 3 Square hands | 0.037037037037 sq yd |
| 4 Square hands | 0.0493827160494 sq yd |
| 5 Square hands | 0.0617283950617 sq yd |
| 10 Square hands | 0.123456790123 sq yd |
| 20 Square hands | 0.246913580247 sq yd |
| 25 Square hands | 0.308641975309 sq yd |
| 50 Square hands | 0.617283950617 sq yd |
| 100 Square hands | 1.23456790123 sq yd |
| Reference | Square hands (sq hh) | Square yards (sq yd) |
|---|---|---|
| A sheet of A4 paper | 6.04211 sq hh | 0.0745939 sq yd |
| A tennis court | 25265.1 sq hh | 311.914 sq yd |
| A football pitch | 691689 sq hh | 8539.37 sq yd |
| One hectare | 968752 sq hh | 11959.9 sq yd |
| Central Park, New York | 330344411 sq hh | 4078326 sq yd |
The square hand is a unit of area equal to sixteen square inches, or 103.2256 square centimetres. Its symbol is sq hh. A hand is four inches, so a square hand is a square four inches on a side, roughly the area of an adult palm. It is a complete and consistent unit that almost nobody has ever needed, because the hand it derives from measures one thing only.
That one thing is horses. The height of a horse or pony is measured at the withers, the ridge between the shoulder blades, and it is given in hands almost everywhere in the world, including in countries that are otherwise entirely metric. A hand was fixed at four inches by an English statute of 1541 under Henry VIII, and the equestrian world has held to that figure ever since.
The notation contains a trap worth knowing. A horse described as 15.2 hands is not fifteen and two tenths but fifteen hands and two inches, which is 62 inches or 157.5 centimetres. The digit after the point runs from 0 to 3 and then rolls over, so 15.3 is followed by 16.0. Anyone converting a list of horse heights with ordinary decimal arithmetic will produce numbers that are wrong by up to three inches.
Where the boundary between pony and horse falls is decided by this measurement. Most classifications put it at 14.2 hands, which is 58 inches or 147.3 centimetres, and competition classes at every level are drawn on the same scale. Because a placing can depend on a fraction of an inch, official measurement is a regulated procedure carried out on a level surface by an approved measurer.
The area form has never followed the length into use. Body-derived units were invented for laying along things, the height of an animal, the length of a cloth, the depth of water, and not for enclosing ground, which is why the acre and the chain came from ploughing rather than from anatomy. A square hand is simply what appears when the rule for forming areas is applied to a unit that had no such purpose.
As a quantity it is easy enough to place. A hundred square centimetres is a large sticky note, a beer mat and a half, or the palm of a hand, which is the same comparison used to estimate burn area in first aid. Sixteen square hands make a square foot, and 2304 of them make a square yard.
One square hand equals 16 square inches, about 103.23 square centimetres, or about 0.0103 square metres.
The square yard is a unit of area equal to nine square feet, or 0.83612736 square metres exactly. Its symbol is sq yd, sometimes written yd². It is the area of a square one yard on a side, and 4840 of them make an acre. It occupies the awkward middle of the imperial ladder: too large for a workshop, too small for a field, and used mainly for surfaces that are laid rather than built.
Ground coverings are its main business. Turf is sold and laid by the square yard, asphalt paving and road resurfacing are measured in square yards in the United States, and carpet was priced that way for most of the twentieth century before American retailers moved to the square foot. Anything that arrives on a roll or a pallet and is spread out tends to be counted in this unit.
Textiles use it in an indirect but important way. Cloth is bought by the linear yard off a roll of known width, but its weight is specified in ounces per square yard, which is what allows two fabrics of different widths to be compared. A shirting might be four ounces per square yard and a heavy canvas eighteen, and those numbers describe the cloth more usefully than any measurement of the bolt does.
It also carries a large part of the South Asian property market. In Pakistan and northern India, plots are commonly sold in gaz, which is the square yard under a local name, so a house plot might be advertised at 240 gaz. Larger holdings switch to the marla and the kanal, both of which are defined as multiples of the square yard, so the whole regional system rests on this unit even where the English name is never used.
Its relationship to the rest of the imperial ladder is unusually clean at one step and unusually messy at the next. Nine square feet is easy; 1296 square inches and 4840 to the acre are not. That mixture is characteristic of a system built from body measures and ploughing practice rather than from a single decimal idea.
Conversion to metric is exact but not memorable: one square yard is 0.83612736 square metres and one square metre is 1.19599 square yards. A rough rule that a square metre is about a fifth larger than a square yard is close enough for judging a room, though not for ordering material.
One square yard equals 9 square feet, 1296 square inches, about 0.8361 square metres, or about 0.000207 acres.