# Convert Second to Hour

Please provide values below to convert second [s] to hour [h], or *vice versa*.

### Second

**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.

### Hour

**Definition:** An hour (symbol: h) is a unit of time conventionally defined as 1/24 of a day and 3,600 seconds. In Coordinated Universal Time, a negative or positive leap second may be incorporated to keep the hour within 0.9 seconds of universal time, making an hour either 3,599 or 3,601 seconds in some cases.

**History/origin:** The term "hour" is derived from the Anglo-Norman "houre," which was in use around the 13^{th} century.

There have been many definitions of the hour throughout history based on culture or region, such as the hour being divided into 1/12 of a period daylight or darkness. It is believed that the custom of dividing the cycle of day and night into 24 periods began with the ancient Egyptians.

**Current use:** The hour is used globally as a unit of time. Most forms of employment require a certain number of hours worked per day, with compensation being based on the measured or expected hours worked. Durations starting from 30 minutes (half an hour) are commonly used colloquially.

### Second to Hour Conversion Table

Second [s] | Hour [h] |
---|---|

0.01 s | 2.7777777777778E-6 h |

0.1 s | 2.77778E-5 h |

1 s | 0.0002777778 h |

2 s | 0.0005555556 h |

3 s | 0.0008333333 h |

5 s | 0.0013888889 h |

10 s | 0.0027777778 h |

20 s | 0.0055555556 h |

50 s | 0.0138888889 h |

100 s | 0.0277777778 h |

1000 s | 0.2777777778 h |

### How to Convert Second to Hour

1 s = 0.0002777778 h

1 h = 3600 s

**Example:** convert 15 s to h:

15 s = 15 × 0.0002777778 h = 0.0041666667 h