A hectometre (American spelling: hectometer, symbol hm) is a somewhat uncommonly used unit of length in the metric system, equal to one hundred metres.
- For area the square hectometre (hm2) is a common unit. It is also known by the name hectare (ha), meaning 100 ares (100 a). The are is a measurement of area the size of 1 decametre by 1 decametre, which is 10 metres by 10 metres. Hence 100 are equals an area with dimensions 100 m by 100 m — 1 hectometre by 1 hectometre, the square hectometre — equalling 10,000 square metres (10,000 m2).
- For volumes the cubic hectometre (hm3) is also used, 100 m by 100 m by 100 m equalling 1,000,000 cubic metres (1,000,000 m3).
Template:SI units of length