Leap Years to Seconds (yr (366) to s)
1 leap year equals 31,622,400 seconds exactly.
How to convert leap years to seconds
To convert leap years to seconds, multiply the number of leap years by 31,622,400. This factor is exact. To go the other way, multiply seconds by 3.162315321×10⁻⁸ (rounded).
seconds = leap years × 31,622,400
Example: 10 leap years = 316,224,000 seconds.
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
Second (s)
The SI base unit of time, defined by the radiation frequency of the cesium-133 atom: 9,192,631,770 cycles per second.
Our word second is a leftover of Latin. Medieval scholars divided a degree, and later the hour, into 60 parts called pars minuta prima, the first small part, and divided those again into pars minuta secunda, the second small part. NIST traces the roots further back: Babylonian and Greek astronomers split the circle into 360 degrees, and around 150 C.E. Ptolemy split each degree into 60 minutes and each minute into 60 seconds. Clocks that could show seconds appeared only in the later 16th century, and Christiaan Huygens's pendulum clock of 1656 was the first able to keep time accurately to the second.
For most of history the second was a fraction of a day, and in 1956 it was redefined as a fraction of the tropical year, a definition the SI took over in 1960. In 1967 the 13th CGPM switched to atoms: 9,192,631,770 periods of the radiation tied to a hyperfine transition of caesium-133. The 2019 SI revision restated this by fixing the caesium frequency at 9,192,631,770 hertz. NIST reports that commercial caesium clocks stay within about a three-millionth of a second per year, and experimental clocks based on other atoms are roughly ten thousand times more precise.
The second is the reference unit for time on this site.
Sources: NIST: the second and the SI redefinition; BIPM: SI Brochure, 9th edition; Wikipedia: Second
Related conversions
- Seconds to leap years (reverse)
- Leap years to minutes
- Leap years to hours
- Leap years to days
- Leap years to weeks
- Leap years to months
- Leap years to years
- Minutes to seconds
- Hours to seconds
- Days to seconds
- Weeks to seconds
- Months to seconds
- Years to seconds
- Milliseconds to seconds
- Microseconds to seconds
- Nanoseconds to seconds
- Decades to seconds
- Centuries to seconds
- Millennia to seconds
See all time units.