The hectometre, (SI symbol: hm[1]), spelt hectometer in American and Philippine English, is a unit of length in the International System of Units (SI), equal to one hundred metres[2] and to one tenth of a kilometre.

The word comes from a combination of "metre" and the SI prefix "hecto-", meaning "hundred".

[citation needed] A football field (either soccer or American) is approximately 1 hectometre in length.

[4][5] The hectare (ha), a common metric unit for land area, is equal to one square hectometre (hm2).

The hectometer has sometimes been used for expressing the distance to a target in warfare.