How Many Seconds Are in a Day?
Get the direct answer, then convert days or break a duration down without doing the arithmetic yourself.
1 standard 24-hour day
24 hours × 60 minutes × 60 seconds
The 86,400-second calculation
A standard day is 24 hours. Each hour has 60 minutes and each minute has 60 seconds, so 24 × 60 × 60 = 86,400 seconds. NIST lists the accepted time unit conversion as 1 day = 24 hours = 86,400 seconds.
Convert any number of days or seconds
Choose Days → seconds to multiply by 86,400. Choose Seconds → duration to divide by 86,400 and see the leftover hours, minutes, and seconds. Quick values cover half a day, multiple days, one hour, and one week.
Standard duration versus a local clock day
This calculator converts the standard unit of duration. A local calendar date can span 23 or 25 clock hours where daylight saving time starts or ends. That civil-time exception does not change the unit conversion used here.
Why Earth rotation and UTC need a footnote
Earth does not rotate at a perfectly fixed rate. Coordinated Universal Time has historically used leap seconds to stay close to astronomical time, so an affected UTC date could contain one extra labeled second. For ordinary schedules, math, and unit conversion, use 86,400 seconds per day.
Frequently asked questions
How many seconds are in a day?
A standard 24-hour day has 86,400 seconds: 24 hours × 60 minutes × 60 seconds.
How many seconds are in 24 hours?
There are 86,400 seconds in 24 hours. Each hour contains 3,600 seconds, so 24 × 3,600 = 86,400.
Are there always exactly 86,400 seconds between local midnights?
Not always. In places that change clocks for daylight saving time, a local civil day can have 23 or 25 clock hours. The converter uses the standard duration unit: 1 day = 86,400 seconds.
Can a UTC day include a leap second?
Historically, a positive leap second could make a UTC date contain 86,401 labeled seconds. The standard unit conversion remains 86,400 seconds per day.
How do I convert days to seconds?
Multiply the number of days by 86,400. For example, 2 days × 86,400 = 172,800 seconds.
How do I convert seconds back to days?
Divide seconds by 86,400. The calculator also separates the remainder into full hours, minutes, and seconds.