Leap Years to Hours (yr (366) to h)
1 leap year equals 8,784 hours exactly.
How to convert leap years to hours
To convert leap years to hours, multiply the number of leap years by 8,784. This factor is exact. To go the other way, multiply hours by 0.0001138433515 (rounded).
hours = leap years × 8,784
Example: 10 leap years = 87,840 hours.
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
Leap Year (yr (366))
A calendar year of exactly 366 days, with the leap day on February 29.
Julius Caesar's edict, effective 1 January 45 BC, turned the Roman calendar into a solar one with an extra day every fourth year. The English phrase is thought to come from weekdays: a fixed date normally moves ahead one weekday each year, but after a leap day it moves two, appearing to leap over one. The extra day is 29 February, used since about the fifteenth century, and British law recognized it formally in 1750.
A leap year has 366 days, or 31,622,400 seconds. The Gregorian rule, which now governs most of the world, makes a year a leap year when divisible by four, except century years that are not divisible by 400. So 2000 was a leap year and 1900 was not. That leaves 97 leap years in each 400-year cycle and a mean year of 365.2425 days, close to the tropical year.
1 leap year = 31,622,400 seconds (exactly).
Sources: Wikipedia: Leap year; Wikipedia: Common year
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
Related conversions
- Hours to leap years (reverse)
- Leap years to seconds
- Leap years to minutes
- Leap years to days
- Leap years to weeks
- Leap years to months
- Leap years to years
- Seconds to hours
- Minutes to hours
- Days to hours
- Weeks to hours
- Months to hours
- Years to hours
- Milliseconds to hours
- Microseconds to hours
- Nanoseconds to hours
- Decades to hours
- Centuries to hours
- Millennia to hours
See all time units.