Decisecond

A decisecond is a unit of time equal to one tenth of a second, or 0.1 seconds. It is formed by applying the deci- prefix to the second. While recognized as a valid time unit, the decisecond is not a standard named SI unit and is used only in certain contexts. In many scientific and technical documents, time is more commonly expressed directly in seconds or in smaller units such as milliseconds.

Converting between units, 1 decisecond equals 0.1 seconds, which is the same as 100 milliseconds. Conversely, 1 second equals 10 deciseconds, and 1 decisecond equals 10 centiseconds (0.01 seconds). This places the decisecond between the centisecond (0.01 s) and the second in terms of granularity.

Usage and context vary. The decisecond is occasionally employed when coarse timing is sufficient, such as in some sports statistics, basic reaction-time measurements, or historical datasets. In modern practice, however, more precise or standard representations are generally preferred, with times expressed in seconds or milliseconds. When converting, an example is that 2.7 ds equals 0.27 seconds.

See also: centisecond, millisecond, second.