Conversion from Day (d) to Second (s) and vice versa

Updated on by Stefan Banse

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


Info about "Day"

Although the day (d) (Latin: dies) is not part of the International SI System of Units, it is indirectly approved for use with the SI through its definition that a day has 24 hours, and it is indirectly permitted for use with the SI. This is because the second form the official SI base value.

Therefore, 1 day equals 24 hours; 1440 minutes = 86,400 seconds 1 second equals 0.0000115741 days.

For thousands of years, the astronomical day (i.e., the time from sunrise to sunrise again) was the historical basic unit of time. The first reliable time measurements were made by the Egyptians in daylight using sundials, which they divided into 12 units according to their usual system of twelve numbers. At night, they used the position of the 12 stars to measure the time at night. It was not yet so important as days were longer in summer than in winter. Basically, the day and night were divided into twelve time periods. It was only 2,000 years ago that Greek astronomers divided the day into hours of equal length.

The day as the basis for time was not replaced by the second until the middle of the 20th century. With the use of modern quartz clocks, it was proven that the astronomical day (i.e., one revolution of the Earth) is constantly becoming somewhat slower. This confirmed the assumption that magma shifts beneath the earth's mantle and also the tides slow down the Earth's rotation. Therefore, since 1956, the second has been defined in such a way that it is measured by an atomic clock and a leap second must be added to the calendar year every 2 to 5 years. Hence, a day that is actually 86,400.003 atomic seconds long is always 86,400 seconds long, and from time to time, it has a one-off of 86,401 seconds.

Info about "Second"

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 Day (d) to Second (s) and vice versa

The abbreviation for the "Time unit Day" is d. The abbreviation for the "Time unit Second" is s.

Formula for the conversion of Day (d) to Second (s) and vice versa

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

 Conversion formula Day to Second 

Determine the number of Second from Day

Day × 86400.000000553

Formula for the conversion of Second (s) to Day (d)

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

 Conversion formula Second to Day 

Determine the number of Day from Second

Second × 1.1574074074E-5

Overview table: How many Day are how many Second?

Day d ⇒ Second s
0.01 d  are  864 s
0.02 d  are  1 728 s
0.03 d  are  2 592 s
0.04 d  are  3 456 s
0.05 d  are  4 320 s
0.06 d  are  5 184 s
0.07 d  are  6 048 s
0.08 d  are  6 912 s
0.09 d  are  7 776 s
0.10 d  are  8 640 s
0.20 d  are  17 280 s
0.30 d  are  25 920 s
0.40 d  are  34 560 s
0.50 d  are  43 200 s
0.60 d  are  51 840 s
0.70 d  are  60 480 s
0.80 d  are  69 120 s
0.90 d  are  77 760 s
1 d  corresponds to  86 400 s
2 d  are  172 800 s
3 d  are  259 200 s
4 d  are  345 600 s
5 d  are  432 000 s
6 d  are  518 400 s
7 d  are  604 800 s
8 d  are  691 200 s
9 d  are  777 600 s
10 d  are  864 000 s
20 d  are  1 728 000.00001 s
30 d  are  2 592 000.00001 s
40 d  are  3 456 000.00002 s
50 d  are  4 320 000.00002 s
60 d  are  5 184 000.00003 s
70 d  are  6 048 000.00003 s
80 d  are  6 912 000.00004 s
90 d  are  7 776 000.00005 s
100 d  are  8 640 000.00005 s
200 d  are  17 280 000.00011 s
300 d  are  25 920 000.00016 s
400 d  are  34 560 000.00022 s
500 d  are  43 200 000.00027 s
600 d  are  51 840 000.00033 s
700 d  are  60 480 000.00038 s
800 d  are  69 120 000.00044 s
900 d  are  77 760 000.00049 s
1 000 d  are  86 400 000.00055 s

Overview table: How many Second are how many Day?

Second s ⇒ Day d
0.90 s  are  0.00001 d
1 s  corresponds to  0.00001 d
2 s  are  0.00002 d
3 s  are  0.00003 d
4 s  are  0.00004 d
5 s  are  0.00005 d
6 s  are  0.00006 d
7 s  are  0.00008 d
8 s  are  0.00009 d
9 s  are  0.00010 d
10 s  are  0.00011 d
20 s  are  0.00023 d
30 s  are  0.00034 d
40 s  are  0.00046 d
50 s  are  0.00057 d
60 s  are  0.00069 d
70 s  are  0.00081 d
80 s  are  0.00092 d
90 s  are  0.00104 d
100 s  are  0.00115 d
200 s  are  0.00231 d
300 s  are  0.00347 d
400 s  are  0.00463 d
500 s  are  0.00578 d
600 s  are  0.00694 d
700 s  are  0.00810 d
800 s  are  0.00925 d
900 s  are  0.01041 d
1 000 s  are  0.01157 d

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