Convert Day to Second
Use this free converter to change days (d) into seconds (s). Day and second both measure time. As a quick reference, 1 d equals 86400 s, and 1 s equals 0.000011574074 d.
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Second (s)
86400
1 d = 86400 s
Time conversion table
| Day | Second |
|---|---|
| 0.01 | 864 |
| 0.1 | 8640 |
| 0.5 | 43200 |
| 1 | 86400 |
| 2 | 172800 |
| 3 | 259200 |
| 5 | 432000 |
| 10 | 864000 |
| 20 | 1728000 |
| 25 | 2160000 |
| 50 | 4320000 |
| 100 | 8640000 |
| 1,000 | 86400000 |
How to convert Day to Second
Multiply the day value by 86400 to get seconds.
- Enter the number of days you want to convert.
- The converter instantly shows the equivalent value in seconds.
- Worked example: 15 d × 86400 = 1296000 s.
- Use the swap button to reverse the conversion (second to day).
About these units
Day (d)
- Definition
- A day (d) is the time for one rotation of the Earth, taken as exactly 86,400 seconds.
- History
- The day is one of the oldest natural time units, tied to the cycle of sunlight.
- Current use
- Days are the basic unit of calendars and scheduling everywhere.
Second (s)
- Definition
- The second (s) is the SI base unit of time, defined by the radiation frequency of the caesium-133 atom.
- History
- Once 1/86,400 of a day, it was redefined in 1967 using atomic transitions for far greater precision.
- Current use
- The second is the foundation of timekeeping in science, technology, and daily life.
Frequently asked questions
How many seconds are in a day?
There are 86400 s in 1 d. To convert, multiply the number of days by 86400.
How do I convert days to seconds?
Multiply the day value by 86400 to get seconds. For example, 10 d = 864000 s.
Is this day-to-second converter free?
Yes. This converter is completely free, runs entirely in your browser, and requires no sign-up. Your inputs never leave your device.
Convert Day to other time units
| Unit | 1 Day equals |
|---|---|
| Second (s) | 86400 s |
| Millisecond (ms) | 86400000 ms |
| Microsecond (µs) | 86400000000 µs |
| Minute (min) | 1440 min |
| Hour (h) | 24 h |
| Week (wk) | 0.14285714 wk |
| Month (mo) | 0.032854209 mo |
| Year (yr) | 0.0027378508 yr |