Hectometre

A hectometre (symbol: hm) is a unit of length in the metric system. One hectometre equals 100 metres. The name comprises the prefix 'hecto-', which means one hundred, and 'metre', the base unit of length in the SI (International System of Units).

The hectometre is an accepted SI prefix unit, but its everyday use is not widespread. When measuring intermediate distances, people typically use metres or kilometres (1,000 metres). For this reason, 10 hectometres equal one kilometre.

Calculation and conversion

1 hm = 100 m = 1,000 decimetres = 10,000 centimetres. Conversely, 1 hm = 0.1 km. In terms of area, the square hectometre (hm²) equals 10,000 square metres, which is equivalent to one hectare—the standard unit for measuring agricultural land.

Usage

The hectometre may be used in some road and railway marking systems, where signs indicate precise locations along a route. It is also found in some educational texts that present the prefixes of the metric system: kilo-, hecto-, deca-, deci-, centi-, milli-.

The hecto- prefix

The prefix 'hecto-' (symbol h) multiplies the unit by 100 (10²). It derives from a Greek word meaning one hundred. Apart from hectare, this prefix is rarely used in modern science, since the SI system favours prefixes that increase in steps of three, such as kilo- and milli-.