Metrication in Australia - Variations in Usage

Variations in Usage

Metrication is mostly complete. Road signs are totally metric, as are the speedometers and odometers in motor vehicles and the sale of oil and petrol is by the litre. Vehicle tyre pressures are now commonly talked about in the metric kilopascal units (kPa).

Fruit and vegetables are advertised, sold and weighed by the kilogram, groceries are packed and labelled in metric measures. Schooling is wholly metric. Newspaper reports are mostly in metric terms. In some cases metrication was achieved by changing rounded Imperial values to rounded metric values, as with horse racing (the old furlong is very close to 200 metres) or the size of beer glasses (rounded to the nearest 5mL).

In some cases, goods manufactured to pre-metric standards are available, such as some bolts, nuts, screws and pipe threads and there are some instances where pre-metric measures may still be used:

• Weight is referred to in kilograms, and baby nappy sizes are specified in kilograms only but some parents give their baby's birth weight in pounds and ounces, however this has become less common.
• Heights for official and sporting purposes are given in centimetres. In informal and private contexts a person's height is sometimes stated in feet and inches.
• Domestic and commercial real estate is advertised in square metres or hectares but though crop yields are described in tonnes per hectare, rural land areas are sometimes advertised in acres.
• Weather reports are always in metric terms but some specialised surf reports give wave heights in feet and there are occasional references to "the old century", meaning 100°F, when describing temperatures of 38°C or more.

Imperial measurements are used in preference to metric usually where the product originates or is intended for an American market (printers, hard-disk drives) or when the size increment for a product is a multiple of an inch (televisions and tyres). A few examples are:

• Scuba diving uses metric measures but the altitude for sky diving is routinely given in feet.
• Hot air ballooning uses horizontal distances in nautical miles and horizontal speed in knots, but horizontal distance for visibility or clearance from clouds is in kilometres or metres. Height or altitude is always in feet and vertical speed (rate of climb or descent) is in feet per minute. The training manual warns, "Watch out – aviation charts and your altimeter are calibrated in feet, but topographical maps usually show contours and spot heights in metres!"
• Australia uses metric paper sizes for printing but the term dots per inch (dpi) is still used in printing pictures.
• Historical writing and presentations may include pre-metric units to reflect the context of the era represented.
• Vehicle tyres mark the rim diameter in inches and the width in millimetres. A car tyre marked '165/70R13' has a width of 165 mm, an aspect ratio (profile) of 70% and a 13 inch rim diameter. Tyre pressures are often given in both kilopascals and pounds per square inch.
• TV screens and LCD monitors may use inches as well as centimetres. i.e.; a Plasma screen may be advertised as 42 inches (106 centimetres), and a computer monitor screen will be advertised in inches.