Weeks to Fortnights (wk to fortnight)
1 week equals 0.5 fortnights exactly.
How to convert weeks to fortnights
To convert weeks to fortnights, multiply the number of weeks by 0.5. This factor is exact. To go the other way, multiply fortnights by 2.
fortnights = weeks × 0.5
Example: 10 weeks = 5 fortnights.
Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.
About these units
Week (wk)
Seven days. The seven-day week comes from the ancient Near East and is nearly universal in the modern calendar.
Nothing in the sky produces a seven-day cycle, which makes the week a human invention with a contested pedigree. Babylonians marked the 7th, 14th, 21st and 28th of the lunar month as special, but that was not a continuous cycle. A continuous seven-day cycle tied to the Sabbath is attested in Judaism by the 6th century BC at the latest, and scholars disagree on whether it was borrowed from Babylon or developed independently. The Romans later used a week named for the Sun, the Moon and the five visible planets, and in AD 321 Emperor Constantine decreed it across the empire.
A week is seven days, or 604,800 seconds, and it divides evenly into neither months nor years, which is why calendars shift against it. The ISO 8601 standard starts each week on Monday and assigns week 1 to the week containing the year's first Thursday, so some years have a week 53. Other societies used different lengths: Rome had an eight-day market cycle, and revolutionary France used a ten-day week from 1793 to 1802. The English word comes from Old English wice, meaning a turn or succession.
1 week = 604,800 seconds (exactly).
Sources: Wikipedia: Week; Wikipedia: ISO week date
Fortnight (fortnight)
Fourteen days; short for 'fourteen nights'. Common in British English.
English inherited fortnight from Old English feowertyne niht, fourteen nights, a reminder that early Germanic peoples reckoned time by nights rather than days. It means exactly two weeks, or 14 days, which is 1,209,600 seconds. Many languages lack a single word for the span, so speakers say two weeks or fourteen days instead.
Other languages tend to count inclusively, as in Welsh pythefnos, meaning fifteen nights, matching wythnos for a week, or Spanish quincena and French quinzaine, which all point to fifteen. The Hindu calendar uses paksa for a half of a lunar month. In astronomy a lunar fortnight is half a synodic month, about 14.77 days, which is slightly longer than the calendar fortnight. Neighbouring units are the week, at half a fortnight, and the month, which holds roughly two of them.
1 fortnight = 1,209,600 seconds (exactly).
Sources: Wikipedia: Fortnight
Related conversions
- Fortnights to weeks (reverse)
- Weeks to seconds
- Weeks to minutes
- Weeks to hours
- Weeks to days
- Weeks to months
- Weeks to years
- Weeks to milliseconds
- Weeks to microseconds
- Weeks to nanoseconds
- Weeks to decades
- Weeks to centuries
- Weeks to millennia
- Seconds to fortnights
- Minutes to fortnights
- Hours to fortnights
- Days to fortnights
- Months to fortnights
- Years to fortnights
See all time units.