hecto

Hecto is a decimal prefix in the metric system that denotes a factor of 100. It is represented by the symbol h and placed before a unit to indicate multiplication by 100. For example, a hectometer is 100 meters, and a hectoliter is 100 liters. The name derives from the Ancient Greek hēkaton, meaning hundred.

The most familiar application of hecto is the hectare, a unit of area used for land measurement. One hectare equals 10,000 square meters, and it is commonly abbreviated ha. In many countries, especially for agriculture and land planning, the hectare remains the standard unit of land area; it is also equal to 0.01 square kilometers. While metric prefixes like kilo- and mega- are widely recognized, hecto is relatively infrequent in everyday measurement outside land areas.

Other hecto-prefixed units exist, such as hectograms (hg), hectoliters (hL), hectometers (hm), and hectoseconds (hs). These are used in specific contexts (for example, in meteorology, food labeling, or construction), but they are far less common than those prefixed by kilo- or deci-. The prefix is one of the official SI prefixes; its use is defined by the same system that governs other prefixes. The symbol h should not be confused with the hour symbol, which is also h in time measurements.