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Convert Day to Millisecond

Please provide values below to convert day [d] to millisecond [ms], or vice versa.

From: day
To: millisecond


Definition: A day (symbol: d) is an accepted, non-SI unit of time that is defined based on the SI (International System of Units) unit of time, the second, and is equal to 86,400 seconds.

History/origin: The term "day" originates from the Old English term "dæg." It is approximately equal to the period required for the Earth to complete a full rotation with respect to the sun. This was later re-defined in terms of the second in 1960, when the second was redefined in terms of Earth's orbital motion in the year 1900. The second, and therefore the day, was again re-defined in 1967 by atomic electron transition.

Current use: The day is a term used worldwide within many contexts one of the most common of which is to refer to a time interval of 24 hours. It is also used to reference daytime, or the period of time during which the sun is above the horizon. The term also has other colloquial uses such as the day of the week and fixed clock periods like 6:00 am to 6:00 pm, among others.


Definition: A millisecond (symbol: ms) is a unit of time based on the SI (International System of Units) base unit of time, the second, and is equal to one-thousandth of a second.

History/origin: The millisecond is based on the SI unit of second, making use of the SI prefix of "milli," meaning 1/1000.

Current use: The millisecond is used to measure smaller durations of time such as frequency of a soundwave, response time of LCD monitors, the wing flap of insects and birds, and time delays, among many others.

Day to Millisecond Conversion Table

Day [d]Millisecond [ms]
0.01 d864000 ms
0.1 d8640000 ms
1 d86400000 ms
2 d172800000 ms
3 d259200000 ms
5 d432000000 ms
10 d864000000 ms
20 d1728000000 ms
50 d4320000000 ms
100 d8640000000 ms
1000 d86400000000 ms

How to Convert Day to Millisecond

1 d = 86400000 ms
1 ms = 1.1574074074074E-8 d

Example: convert 15 d to ms:
15 d = 15 × 86400000 ms = 1296000000 ms

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