# Conversion from Hour (h) to Second (s) and vice versa

Updated on by Stefan Banse

Here you can convert the Time unit Hour into the unit Second and vice versa you can convert Second into Hour. By clicking the "Swap units" icon, you will always obtain the desired conversion in the calculation result, i.e., h to s or s to h. With the following calculator you can also calculate any other Time unit.

The hour (h) (Latin: hora) is not part of the International SI System of Units, but it is permitted for use with the SI. The hour is derived from the base unit second. This makes it a legal unit of measurement.

Here, 1 hour is equal to 3,600 seconds or 1 second is equal to 0.00027778 hours (3,600ths).

For thousands of years—before the hour was officially defined as 3,600 times a second—it was considered the 24th part of a day. But how did the day originally change to a division of the day into 24 hours? In ancient Egypt, sundials were used to divide the day into 24 hours based on the common system (duodecimal system) at the time. The twelve-unit system may have originated historically from the fact that one individual finger links (three links per finger without thumb) were used for counting. Of course, sundials could not be used at night, so the Egyptians used the course of 12 stars to divide the night into 12-time units. This means that even today, the day still has 24 hours.

The hour was only reverted to the basic unit of the second in the middle of the 20th century after it was established and the astronomical day or one revolution of the Earth, was becoming shorter and shorter, albeit only minimally. At the same time, quartz clocks were able to measure time more accurately, making the second the basic unit. To synchronise the present accurate atomic clocks with the duration of the earth's rotation, a leap second had to be inserted every 2 to 5 years for one hour to make 3,601 seconds.

The second (s) is the base unit of time in the International System of Units (SI). Therefore, the second is the physical unit of time measurement.

All other units of time are derived from the second (e.g., 1 minute = 60 seconds, 1 second = 1,000 milliseconds).

Until the middle of the 20th century, the second was defined as the sixtieth part of a minute of the day divided into 24 hours of 60 minutes. Since the rotation of the earth was assumed to be uniform, the length of a day and that of a second always appeared to be the same. It was not until 1934 that the long-held assumption that the Earth's rotation is not uniform was proven. As a result of magma displacements beneath the Earth's mantle and tidal friction, the Earth's rotation gradually slows down and thus the astronomical length of the day becomes longer. It turned out that the continuously improved quartz clocks provided a more consistent measure of time than the Earth's rotation. For this reason, a leap second is now added every 2 to 5 years to synchronise all clocks with the day, which always becomes a few fractions of a second longer.

Since 1967, the second has been defined as 9,192,631,770 times the period of a microwave, which resonates with a selected transition between two energy levels in the cesium atomic resonance. Therefore, it is called the atomic second Based on this definition. Atomic clocks are based on the exact measurement of this transition, and thus supersede quartz clocks in terms of accuracy.

## Basis for conversion Hour (h) to Second (s) and vice versa

The abbreviation for the "Time unit Hour" is h. The abbreviation for the "Time unit Second" is s.

## Formula for the conversion of Hour (h) to Second (s) and vice versa

The calculation from Hour to Second shall be made using the following conversion formula:

Conversion formula Hour to Second

Determine the number of Second from Hour

Hour × 3600

## Formula for the conversion of Second (s) to Hour (h)

The calculation from Second to Hour shall be made using the following conversion formula:

Conversion formula Second to Hour

Determine the number of Hour from Second

Second × 0.000277777777778

## Overview table: How many Hour are how many Second?

Hour h ⇒ Second s
0.01 h  are  36 s
0.02 h  are  72 s
0.03 h  are  108 s
0.04 h  are  144 s
0.05 h  are  180 s
0.06 h  are  216 s
0.07 h  are  252 s
0.08 h  are  288 s
0.09 h  are  324 s
0.10 h  are  360 s
0.20 h  are  720 s
0.30 h  are  1 080 s
0.40 h  are  1 440 s
0.50 h  are  1 800 s
0.60 h  are  2 160 s
0.70 h  are  2 520 s
0.80 h  are  2 880 s
0.90 h  are  3 240 s
1 h  corresponds to  3 600 s
2 h  are  7 200 s
3 h  are  10 800 s
4 h  are  14 400 s
5 h  are  18 000 s
6 h  are  21 600 s
7 h  are  25 200 s
8 h  are  28 800 s
9 h  are  32 400 s
10 h  are  36 000 s
20 h  are  72 000 s
30 h  are  108 000 s
40 h  are  144 000 s
50 h  are  180 000 s
60 h  are  216 000 s
70 h  are  252 000 s
80 h  are  288 000 s
90 h  are  324 000 s
100 h  are  360 000 s
200 h  are  720 000 s
300 h  are  1 080 000 s
400 h  are  1 440 000 s
500 h  are  1 800 000 s
600 h  are  2 160 000 s
700 h  are  2 520 000 s
800 h  are  2 880 000 s
900 h  are  3 240 000 s
1 000 h  are  3 600 000 s

## Overview table: How many Second are how many Hour?

Second s ⇒ Hour h
0.04 s  are  0.00001 h
0.05 s  are  0.00001 h
0.06 s  are  0.00001 h
0.07 s  are  0.00001 h
0.08 s  are  0.00002 h
0.09 s  are  0.00002 h
0.10 s  are  0.00002 h
0.20 s  are  0.00005 h
0.30 s  are  0.00008 h
0.40 s  are  0.00011 h
0.50 s  are  0.00013 h
0.60 s  are  0.00016 h
0.70 s  are  0.00019 h
0.80 s  are  0.00022 h
0.90 s  are  0.00025 h
1 s  corresponds to  0.00027 h
2 s  are  0.00055 h
3 s  are  0.00083 h
4 s  are  0.00111 h
5 s  are  0.00138 h
6 s  are  0.00166 h
7 s  are  0.00194 h
8 s  are  0.00222 h
9 s  are  0.00250 h
10 s  are  0.00277 h
20 s  are  0.00555 h
30 s  are  0.00833 h
40 s  are  0.01111 h
50 s  are  0.01388 h
60 s  are  0.01666 h
70 s  are  0.01944 h
80 s  are  0.02222 h
90 s  are  0.02500 h
100 s  are  0.02777 h
200 s  are  0.05555 h
300 s  are  0.08333 h
400 s  are  0.11111 h
500 s  are  0.13888 h
600 s  are  0.16666 h
700 s  are  0.19444 h
800 s  are  0.22222 h
900 s  are  0.25000 h
1 000 s  are  0.27777 h

## Source information

As source for the information in the "Time units" category, we have used in particular:

## Last update on November 4, 2021

The pages of the "Time units" category were last editorially reviewed by Stefan Banse on November 4, 2021. They all correspond to the current status.

### Previous changes on April 24, 2021

• April 24, 2021: Publication of the time units converter.
• Editorial revision of all texts in this category