Days to Fortnights (d to fortnight)
1 day equals 0.07142857143 fortnights (rounded).
How to convert days to fortnights
To convert days to fortnights, multiply the number of days by 0.07142857143. The factor is rounded to 10 significant digits. To go the other way, multiply fortnights by 14.
fortnights = days × 0.07142857143
Example: 10 days = 0.7142857143 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
Day (d)
24 hours or 86,400 seconds. The mean solar day; the actual rotation of the Earth is about 4 minutes shorter (see sidereal day).
Old English dæg is the root of our day, with close cousins in German Tag, Dutch dag and Icelandic dagur, all descending from Proto-Germanic dagaz. It is the oldest unit here, because the cycle of light and dark needs no instrument. Yet the day we count is a constructed average: the actual interval from one noon to the next varies through the year by up to about 7.9 seconds, because Earth's orbit is elliptical and its axis is tilted.
Astronomers smooth this out with a fictitious mean Sun, giving the mean solar day, and the day in the SI sense is fixed at exactly 86,400 seconds. Reality has drifted slightly: the mean solar day has recently averaged about 86,400.002 seconds, and tidal drag from the Moon is lengthening it by about 2 milliseconds per century. That is why 27 leap seconds were added to UTC between 1972 and 2022. One rotation measured against the distant stars is shorter, about 23 hours 56 minutes 4.09 seconds, and a year contains one more of these sidereal days than solar days.
1 day = 86,400 seconds (exactly).
Sources: Wikipedia: Day; BIPM: SI Brochure, 9th edition
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 days (reverse)
- Days to seconds
- Days to minutes
- Days to hours
- Days to weeks
- Days to months
- Days to years
- Days to milliseconds
- Days to microseconds
- Days to nanoseconds
- Days to decades
- Days to centuries
- Days to millennia
- Seconds to fortnights
- Minutes to fortnights
- Hours to fortnights
- Weeks to fortnights
- Months to fortnights
- Years to fortnights
See all time units.