A hyphenation algorithm is a set of rules, especially one codified for implementation in a computer program, that decides at which points a word can be broken over two lines with a hyphen. For example, a hyphenation algorithm might decide that impeachment can be broken as impeach‧ment or im‧peachment but not impe‧achment.

One of the reasons for the complexity of the rules of wordbreaking is that different "dialects" of English tend to differ on hyphenation [citation needed]: American English tends to work on sound, but British English tends to look to the origins of the word and then to sound. There are also a large number of exceptions, which further complicates matters.