How to convert days to seconds
To convert a measurement in days to seconds, multiply the value by 86,400. The conversion factor comes from the relationship between both units and the second.
For example, to convert 5 d to seconds: 5 × 86,400 = 432,000 s.
What is a day?
A day is a unit of time equal to 24 hours or 86,400 seconds, based on one full rotation of the Earth on its axis. The day is humanity's oldest natural time unit, set by the cycle of light and dark. The exact 86,400-second day is a civil convention; the true solar day varies slightly through the year.
Common uses of days include: Calendars and daily scheduling; Project timelines and deadlines; Shipping and delivery estimates; Medication dosing intervals.
What is a second?
A second is the SI base unit of time, defined by the radiation period of the caesium-133 atom (9,192,631,770 cycles). Historically defined as 1/86,400 of a mean solar day, the second was redefined in 1967 using atomic clocks, making it one of the most precisely realized units in all of science.
Common uses of seconds include: Scientific timing and physics experiments; Sports timing and lap records; Computing timeouts and latency measurements; Everyday stopwatch and countdown timing.
Days to seconds worked examples
Here are some common values converted:
1 d = 86,400 s 5 d = 432,000 s 10 d = 864,000 s 50 d = 4,320,000 s 100 d = 8,640,000 s
Frequently asked questions
How many seconds are in one day?
One day (d) equals 86,400 seconds (s). Multiply any value in days by 86,400 to convert to seconds.
How do I convert days to seconds?
Multiply the value in days by 86,400. For example, 5 d × 86,400 = 432,000 s.
How do I convert seconds to days?
Multiply the value in seconds by 0.000011574074, or divide by 86,400. Use the swap button on the converter above to reverse the direction.
Is the day to second conversion exact?
Fixed units (second through week) are exact. Month and year use the average Gregorian calendar length (30.44 and 365.2425 days) since these vary in practice.
What is the formula for days to seconds?
The formula is: s = d × 86,400. This comes from the definition of both units relative to the second.