29 May 2022

## Blog Post # How Many Milliseconds Are In A Year

Definition: A millisecond is (symbol: ms) is a unit of the time based on these SI (International System of Units) base units of time, the second, and is equal to one-thousandth of a second.

History/origin: The millisecond is based on the SI unit of second, making use of the SI prefix of “milli,” meaning 1/1000.

Current use: The millisecond is used to measure smaller durations of time such as frequency of a soundwave, response time of LCD monitors, the wing flap of insects and birds, and time delays, among many others.

## How to Convert Millisecond to Second

1 ms = 0.001 s
1 s = 1000 ms

Example: convert 15 ms to s:
15 ms = 15 × 0.001 s = 0.015 s

## How many milliseconds are in a whole year?

How Many Milliseconds in a Year? There are 31556952000 milliseconds in a year. 1 Year is equal to 31556952000 Milliseconds.

## Second

Definition: A second is these base units of the time in the International System of a Units (SI). It is defined based on a cesium frequency, ΔνC, “by taking these unperturbed ground-state hyperfine transition frequencies of this cesium-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 these previous definitions, except that these conditions are more rigorously defined.

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

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

The second was also defined as the fraction of an extrapolated year in the late 1940s with the advent of a quartz crystal are oscillator of clocks. This results in the second defined as “1/31,556,925.9747 of the tropical of 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 these ground states of this cesium-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 the time, the second and its multiples are ubiquitous. There are few, if any, modern applications in which time is measured in the form other than the second and its multiples.

## How to Convert Millisecond to Second

1 ms = 0.001 s
1 s = 1000 ms

Example: convert 15 ms to s:
15 ms = 15 × 0.001 s = 0.015 s