Days to Seconds Conversion (d to s)

Days to Seconds Converter

Enter the time in days below to convert it to seconds.

Result in Seconds:

21 d = 1,814,400 s

How to Convert Days to Seconds

To convert a measurement in days to a measurement in seconds, multiply the time by the following conversion ratio: 86,400 seconds/day.

Since one day is equal to 86,400 seconds, you can use this simple formula to convert:

seconds = days × 86,400

The time in seconds is equal to the time in days multiplied by 86,400.

For example, here's how to convert 5 days to seconds using the formula above.

seconds = (5 d × 86,400) = 432,000 s

conversion scale showing days and equivalent seconds time values

How Many Seconds Are in a Day?

There are 86,400 seconds in a day, which is why we use this value in the formula above.

1 d = 86,400 s

Days and seconds are both units used to measure time. Keep reading to learn more about each unit of measure.

What Is a Day?

One day is the time it takes for the Earth to complete a single 360-degree rotation about its axis. There are 24 hours in a day.

The day is an SI accepted unit for time for use with the metric system. Days can be abbreviated as d; for example, 1 day can be written as 1 d.

Learn more about days.

What Is a Second?

The second has historically been defined as 1/60 of a minute or 1/86,400 of a day. According to the SI definition, the second is the duration of 9,192,631,770 oscillations of the frequency of light emitted from the atomic transition between the two hyperfine levels of the unperturbed ground state of the caesium 133 atom.^[1]

The second is the SI base unit for time in the metric system. Seconds can be abbreviated as s, and are also sometimes abbreviated as sec. For example, 1 second can be written as 1 s or 1 sec.

Learn more about seconds.

Day to Second Conversion Table

Table showing various day measurements converted to seconds.
Days	Seconds
0.0001 d	8.64 s
0.0002 d	17.28 s
0.0003 d	25.92 s
0.0004 d	34.56 s
0.0005 d	43.2 s
0.0006 d	51.84 s
0.0007 d	60.48 s
0.0008 d	69.12 s
0.0009 d	77.76 s
0.001 d	86.4 s
0.002 d	172.8 s
0.003 d	259.2 s
0.004 d	345.6 s
0.005 d	432 s
0.006 d	518.4 s
0.007 d	604.8 s
0.008 d	691.2 s
0.009 d	777.6 s
0.01 d	864 s
0.02 d	1,728 s
0.03 d	2,592 s
0.04 d	3,456 s
0.05 d	4,320 s
0.06 d	5,184 s
0.07 d	6,048 s
0.08 d	6,912 s
0.09 d	7,776 s
0.1 d	8,640 s
0.2 d	17,280 s
0.3 d	25,920 s
0.4 d	34,560 s
0.5 d	43,200 s
0.6 d	51,840 s
0.7 d	60,480 s
0.8 d	69,120 s
0.9 d	77,760 s
1 d	86,400 s

Table showing various day measurements converted to seconds.

Days

Seconds

0.0001 d

8.64 s

0.0002 d

17.28 s

0.0003 d

25.92 s

0.0004 d

34.56 s

0.0005 d

43.2 s

0.0006 d

51.84 s

0.0007 d

60.48 s

0.0008 d

69.12 s

0.0009 d

77.76 s

0.001 d

86.4 s

0.002 d

172.8 s

0.003 d

259.2 s

0.004 d

345.6 s

0.005 d

432 s

0.006 d

518.4 s

0.007 d

604.8 s

0.008 d

691.2 s

0.009 d

777.6 s

0.01 d

864 s

0.02 d

1,728 s

0.03 d

2,592 s

0.04 d

3,456 s

0.05 d

4,320 s

0.06 d

5,184 s

0.07 d

6,048 s

0.08 d

6,912 s

0.09 d

7,776 s

0.1 d

8,640 s

0.2 d

17,280 s

0.3 d

25,920 s

0.4 d

34,560 s

0.5 d

43,200 s

0.6 d

51,840 s

0.7 d

60,480 s

0.8 d

69,120 s

0.9 d

77,760 s

1 d

86,400 s

References

International Bureau of Weights and Measures, The International System of Units, 9th Edition, 2019, https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf