Convert days to milliseconds
Converting days to milliseconds is a common time task, whether you are checking a recipe, a spec sheet, a travel distance or a homework problem. Since 1 d equals 86,400,000 ms, the math is a single multiplication — and this page does it for you instantly, with the formula, a table of common values and answers to the questions people ask most.
Exact factor
How to convert days to milliseconds
To convert days to milliseconds, multiply the number of days by 86,400,000. For example, 10 d × 86,400,000 = 864,000,000 ms.
ms = d × 86,400,000
- Write down the value in days you want to convert.
- Multiply it by 86,400,000 (the exact d→ms factor).
- The result is your value in milliseconds. Check it below with the converter or the table.
Conversion table
Common values of days and their equivalents in milliseconds:
| d | ms |
|---|---|
| 1 | 86,400,000 |
| 2 | 172,800,000 |
| 3 | 259,200,000 |
| 4 | 345,600,000 |
| 5 | 432,000,000 |
| 10 | 864,000,000 |
| 20 | 1,728,000,000 |
| 25 | 2,160,000,000 |
| 50 | 4,320,000,000 |
| 100 | 8,640,000,000 |
| 250 | 21,600,000,000 |
| 500 | 43,200,000,000 |
About these units
Day (d). A day equals 24 hours or 86,400 seconds, approximating one rotation of the Earth. Calendars, deadlines and project plans are built on days.
Millisecond (ms). A millisecond is one thousandth of a second, the typical scale of computer response times and camera flashes. Network latency and frame durations are measured in milliseconds.
Frequently asked questions
How do I convert days to milliseconds?
To convert days to milliseconds, multiply the number of days by 86,400,000. For example, 10 d × 86,400,000 = 864,000,000 ms. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many milliseconds are in 1 day?
1 d = 86,400,000 ms. That is the fixed relationship used by this converter and by international standards.
How many days are in 1 millisecond?
1 ms = 0.0000000115741 d. If you are converting in the opposite direction, use our Millisecond to Day converter for the dedicated table and FAQ.
Is the days to milliseconds conversion exact?
Yes. Both units are defined by international agreement, so the factor of 86,400,000 is exact. Displayed results are rounded to 6 significant digits only for readability.
What is day used for?
A day equals 24 hours or 86,400 seconds, approximating one rotation of the Earth. Calendars, deadlines and project plans are built on days.