Time Converter
60 min
- 3,600,000,000,000
- ns
- 3,600,000
- ms
- 3,600
- s
- 60
- min
- 1
- h
- 0.0416667
- d
- 0.00595238
- wk
- 0.00136895
- mo
The time converter handles nine units from nanoseconds to years. Everything up to a week is exact; months and years are not, because neither has a fixed length. The figures used here are the Gregorian averages, and the page says so rather than pretending otherwise.
How it works
- Exact: nanosecond, millisecond, second, minute (60 s), hour (3,600 s), day (86,400 s), week (604,800 s).
- Year: 31,556,952 seconds, the Gregorian average of 365.2425 days that accounts for the leap-year rule.
- Month: 2,629,746 seconds, simply the average year divided by twelve. No calendar month is actually this long.
The day is exactly 86,400 seconds by definition, but a real day occasionally is not. Leap seconds have added a second to 27 days since 1972. The International Telecommunication Union voted in 2022 to discontinue them by 2035.
Examples
A working year in hours
Value
1
From
Year (Gregorian)
To
Hour
Result
8,765.82 h
365.2425 days × 24. The familiar "8,760 hours in a year" assumes exactly 365 days and is about six hours short.
Where the month approximation shows
Value
1
From
Month (average)
To
Day
Result
30.436875 d
No month is 30.44 days long. They are 28, 29, 30 or 31. Use this for rough planning and a calendar for anything with a deadline.
Frequently asked questions
Why is a month 30.44 days here?
Because it is the average: the Gregorian year of 365.2425 days divided by twelve. No actual month is that length, so any calculation that matters (a billing period, a notice period, a deadline) should use real calendar dates rather than this average.
Why is a year not exactly 365 days?
Because Earth takes about 365.2425 days to orbit the Sun under the Gregorian rule, which is why we add a leap day every four years except century years not divisible by 400. That rule is what makes 365.2425 the right average rather than 365.25.
Are leap seconds accounted for?
No. A day is treated as exactly 86,400 seconds. In reality 27 leap seconds have been added since 1972 to keep clocks aligned with Earth’s slightly irregular rotation. The ITU voted in 2022 to stop adding them by 2035.
Which units here are exact?
Everything up to and including the week. Second, minute, hour, day and week are all fixed by definition. Only the month and year involve an averaged approximation.