Hours to Common Years (h to yr (365))
1 hour equals 0.0001141552511 common years (rounded).
How to convert hours to common years
To convert hours to common years, multiply the number of hours by 0.0001141552511. The factor is rounded to 10 significant digits. To go the other way, multiply common years by 8,760.
common years = hours × 0.0001141552511
Example: 10 hours = 0.001141552511 common 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
Hour (h)
60 minutes or 3,600 seconds, one twenty-fourth of a mean solar day.
Egyptian astronomers gave us the twelve. Coffin lids from about 2150 BC show the night divided into exactly 12 intervals, tied to the rising of star groups called decans, and the day was later split into 12 hours with sundials. These were seasonal hours, a twelfth of the daylight, so a summer hour was longer than a winter one. The word itself comes from Greek hora, originally any span of time, through Latin and Old French into English in the 13th century.
Equal hours of 1/24 of a day were probably first proposed by Hipparchus, and mechanical clocks made them the practical choice, since a clock showing seasonal hours had to be readjusted every morning and evening. Today the hour is exactly 3,600 seconds and is a non-SI unit accepted for use with the SI. Civil time still bends it a little: UTC hours have lasted 3,601 seconds 27 times since 1972 to keep clocks within 0.9 seconds of the Earth's rotation. In practice we use it for working shifts, travel times and electricity bills measured in kilowatt-hours.
1 hour = 3,600 seconds (exactly).
Sources: Wikipedia: Hour; BIPM: SI Brochure, 9th edition
Common Year (yr (365))
A calendar year of exactly 365 days, without a leap day.
Calendar makers needed whole numbers of days, so the common year is simply 365 of them, or 31,536,000 seconds at 86,400 seconds per day. It makes up 303 of every 400 years in the Gregorian calendar. Because 365 is 52 weeks plus one day, a common year begins and ends on the same weekday, and each date falls one weekday later than the year before.
The trouble is that the Earth takes about 365.24 days to complete a cycle of seasons, so a common year runs roughly 5 hours, 48 minutes and 46 seconds short of the tropical year. The shortfall adds up to a full day in about four years, which is why leap years exist. NIST lists the 365-day year as an exact conversion, while its tropical and sidereal years are measured quantities that differ in the fifth significant figure.
1 common year = 31,536,000 seconds (exactly).
Sources: Wikipedia: Common year; NIST SP 811 Appendix B.8: factors for units outside the SI
Related conversions
- Common years to hours (reverse)
- Hours to seconds
- Hours to minutes
- Hours to days
- Hours to weeks
- Hours to months
- Hours to years
- Hours to milliseconds
- Hours to microseconds
- Hours to nanoseconds
- Hours to decades
- Hours to centuries
- Hours to millennia
- Seconds to common years
- Minutes to common years
- Days to common years
- Weeks to common years
- Months to common years
- Years to common years
See all time units.