Days to Weeks (d to wk)
1 day equals 0.1428571429 weeks (rounded).
How to convert days to weeks
To convert days to weeks, multiply the number of days by 0.1428571429. The factor is rounded to 10 significant digits. To go the other way, multiply weeks by 7.
weeks = days × 0.1428571429
Example: 10 days = 1.428571429 weeks.
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
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
Related conversions
- Weeks to days (reverse)
- Days to seconds
- Days to minutes
- Days to hours
- Days to months
- Days to years
- Days to milliseconds
- Days to microseconds
- Days to nanoseconds
- Days to decades
- Days to centuries
- Days to millennia
- Days to picoseconds
- Seconds to weeks
- Minutes to weeks
- Hours to weeks
- Months to weeks
- Years to weeks
- Milliseconds to weeks
- Microseconds to weeks
- Nanoseconds to weeks
- Decades to weeks
- Centuries to weeks
- Millennia to weeks
- Picoseconds to weeks
See all time units.