Overview

A fortnight is a conventional unit of time equal to 14 days, or two weeks. It is commonly used in everyday speech and in scheduling in parts of the English‑speaking world. Colloquially, phrases such as "in a fortnight" or "fortnightly" mean "in two weeks" or "every two weeks," respectively.

Measurement and equivalents

By simple conversion, one fortnight equals 14 days, which is 336 hours, 20,160 minutes, or 1,209,600 seconds. Because most calendar months are not an even multiple of 14 days, counting by fortnights across calendar dates causes the weekday of a recurring event to shift when measured against monthly calendars.

Origin and historical notes

The word derives from Old English fēowertyne niht, literally "fourteen nights." The term has been present in English usage for many centuries and appears in historical documents where short intervals of weeks were referenced. It remains a standard lexical item in British and several Commonwealth varieties of English.

Uses and examples

Fortnights are commonly used for informal planning, such as arranging appointments, vacations, or publication schedules. In payroll and finance, some employers pay wages on a fortnightly (every 14 days) basis; this is particularly common in the United Kingdom, Australia and New Zealand. Example: "staff are paid on a fortnightly cycle" means pay dates recur every 14 days.

Distinctions and potential confusion

  • Fortnight = 14 days (unambiguous).
  • Biweekly is commonly used in North America to mean every two weeks, but the term is ambiguous in general English because some people interpret it as "twice a week."
  • Semimonthly means twice a month (for example on the 1st and 15th); semimonthly pay periods do not align exactly with fortnightly pay and produce different annual pay dates.

Notable facts

Related expressions appear in other languages: French speakers often say "quinze jours" (literally "fifteen days") to mean two weeks, while Spanish uses "quincena." Astronomically, a half lunar cycle (from new moon to full moon or vice versa) is close to a fortnight in length but is not exactly 14 days.