Weeks to Julian Years (wk to a)
1 week equals 0.01916495551 Julian years (rounded).
How to convert weeks to Julian years
To convert weeks to Julian years, multiply the number of weeks by 0.01916495551. The factor is rounded to 10 significant digits. To go the other way, multiply Julian years by 52.17857143 (rounded).
Julian years = weeks × 0.01916495551
Example: 10 weeks = 0.1916495551 Julian years.
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
Julian Year (a)
Exactly 365.25 days (31,557,600 seconds). The astronomical standard; a light-year is defined using it.
Astronomers wanted a year that would never change, so they borrowed the average length of the old Julian calendar year: exactly 365.25 days of 86,400 SI seconds, or 31,557,600 seconds. The symbol is a, or aj when it must be told apart from other years. It is not an SI unit, but the IAU lists it among the non-SI units accepted for use in astronomy.
The mean tropical year drifts slightly from one year to the next, so it makes a poor unit, whereas the Julian year is constant because it rests on the SI second. It still approximates both the sidereal and tropical years to within about 0.008 days. The current standard epoch, J2000.0, is exactly 12:00 TT on 1 January 2000, and other Julian epochs are counted in Julian years from it. The light-year is defined as the distance light covers in one Julian year.
1 Julian year = 31,557,600 seconds (exactly).
Sources: Wikipedia: Julian year (astronomy); Wikipedia: Light-second; NIST SP 811 Appendix B.8: factors for units outside the SI
Related conversions
- Julian years 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 Julian years
- Minutes to Julian years
- Hours to Julian years
- Days to Julian years
- Months to Julian years
- Years to Julian years
See all time units.