Day to Second Converter
Convert Day (d) to Second (s) instantly. 1 d = 86,400 s.
Time Converter
21 units available
1 d = 86,400 s
Formula:
s = d × 86,400With your value: 1 d = 86,400 s
How big is that?
Everyday references on a logarithmic scale, all expressed in day so you can sanity-check the result.
Other Day to Second conversions
Day to Second Conversion Table
| Day (d) | Second (s) |
|---|---|
| 0.5 | 43,200 |
| 1 | 86,400 |
| 2 | 172,800 |
| 5 | 432,000 |
| 10 | 864,000 |
| 15 | 1,296,000 |
| 20 | 1,728,000 |
| 25 | 2,160,000 |
| 50 | 4,320,000 |
| 100 | 8,640,000 |
| 250 | 21,600,000 |
| 500 | 43,200,000 |
| 1000 | 86,400,000 |
Second to Day Conversion Table
| Second (s) | Day (d) |
|---|---|
| 0.5 | 5.787037e-6 |
| 1 | 1.157407e-5 |
| 2 | 2.314815e-5 |
| 5 | 5.787037e-5 |
| 10 | 0.000116 |
| 15 | 0.000174 |
| 20 | 0.000231 |
| 25 | 0.000289 |
| 50 | 0.000579 |
| 100 | 0.001157 |
| 250 | 0.002894 |
| 500 | 0.005787 |
| 1000 | 0.011574 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Day (d)
Time
Traceable to the second, defined by fixing the caesium-133 hyperfine transition frequency at 9 192 631 770 Hz.
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
Second (s)
Time
The second is defined by taking the caesium-133 ground-state hyperfine transition frequency to be exactly 9 192 631 770 Hz.
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
How to Convert Day to Second
To convert from Day (d) to Second (s), multiply the value by 86,400.
Formula: s = d × 86,400
Reverse: d = s × 0.0000115741
Step-by-Step Example
- Start with your value in Day. For example: 5 d
- Multiply by the conversion factor: 5 x 86,400
- The result is: 432,000 s
About Day
The day (d) is a unit of time. One day equals 86400 seconds. UnitConvertLab converts it against every other time unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: time calculations, engineering and science, education.
About Second
The second (s) is a unit of time. One second equals 1 second. UnitConvertLab converts it against every other time unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: time calculations, engineering and science, education.
Frequently Asked Questions
How many Second are in 1 Day?
There are exactly 86,400 Second in 1 Day. This means the conversion factor from Day to Second is 86,400.
What is the formula to convert Day to Second?
The formula to convert Day to Second is: s = d × 86,400. For example, to convert 10 Day to Second, you would multiply 10 by 86,400.
What is a Day?
The day (d) is a unit of time. One day equals 86400 seconds. UnitConvertLab converts it against every other time unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What is a Second?
The second (s) is a unit of time. One second equals 1 second. UnitConvertLab converts it against every other time unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What are the common uses of Day?
The Day is commonly used in time calculations, engineering and science, education.
Related Time Conversions
Cite this page
UnitConvertLab. (2026). Day to Second converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/day-to-second