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Convert Second to Year

Please provide values below to convert second [s] to year [y], or vice versa.



Definition: A second is the base unit of time in the International System of Units (SI). It is defined based on cesium frequency, ΔνC, "by taking the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom to be 9,192,632,770 when expressed in hertz, which is equal to s-1." This definition was adopted in late 2018, and is largely the same as the previous definition, except that the conditions are more rigorously defined.

History/origin: Unlike many units that have had numerous definitions throughout history, the second has only had four different definitions.

The second was historically defined as 1/86400 of a day in 1832, which was based on the definition of a day as the approximate amount of time required for the Earth to complete a full rotation cycle relative to the sun.

The second was also defined as a fraction of an extrapolated year in the late 1940s with the advent of quartz crystal oscillator clocks. This resulted in a second defined as "1/31,556,925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time," in 1956. This definition was adopted as part of SI in 1960.

In 1967, the second was defined exactly as "9,192,631,770 times the period of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom." This definition has since been updated as of late 2018 to be more rigorously defined, but otherwise, is effectively the same. This new rigor does not affect how the second is used in everyday life.

Current use: As the SI base unit of time, the second and its multiples are ubiquitous. There are few, if any, modern applications in which time is measured in a form other than the second and its multiples.


Definition: A year (symbol: y, yr, or a) is a measurement of time based on Earth's orbital period around the sun. This is approximated as 365 or 366 days in the Gregorian calendar. Earth's orbit around the sun is seen as the passing of seasons in which weather, daylight hours, vegetation, and soil fertility, among other things, change.

History/origin: Various definitions of a year have been used by different calendars throughout history. The most commonly used calendar for civil affairs today is the Gregorian calendar, a solar calendar which consists of 365 or 366 days, depending on whether or not the year is a leap year. In astronomy, many other definitions of the year exist, such as the sidereal, draconic, lunar, and Gaussian year, among others.

The Gregorian calendar is a calendar that was reformed from the Julian calendar, which was a calendar that itself was reformed from the ancient Roman calendar.

Current use: The definition of a year based on the Gregorian calendar is used worldwide. In some cultures, lunisolar calendars are also used. In astronomy, many different definitions of the year are used, including the Julian year as a unit of time equal to 365.25 days based on the SI (International System of Units) base unit of seconds.

The term "year" is also used to describe periods that are loosely associated to the calendar year, such as the seasonal year, fiscal year, and academic year.

Second to Year Conversion Table

Second [s]Year [y]
0.01 s3.1688087814029E-10 y
0.1 s3.1688087814029E-9 y
1 s3.1688087814029E-8 y
2 s6.3376175628058E-8 y
3 s9.5064263442087E-8 y
5 s1.5844043907014E-7 y
10 s3.1688087814029E-7 y
20 s6.3376175628058E-7 y
50 s1.5844043907014E-6 y
100 s3.1688087814029E-6 y
1000 s3.16881E-5 y

How to Convert Second to Year

1 s = 3.1688087814029E-8 y
1 y = 31557600 s

Example: convert 15 s to y:
15 s = 15 × 3.1688087814029E-8 y = 4.7532131721043E-7 y

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