Time converter
Convert durations from nanoseconds to millennia.
1 Hours = 60 Minutes
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About these units
Time is measured in seconds, the SI base unit, defined by the frequency of a caesium atom. Minutes, hours and days are fixed multiples: a day here is exactly 86 400 seconds.
Months and years are not fixed. Calendar months have 28 to 31 days and years 365 or 366, so this converter uses the average of the Gregorian calendar: a year of 365.2425 days and a month of one twelfth of that, about 30.44 days. For exact calendar dates, use the date calculators.
Astronomers use the Julian year of exactly 365.25 days.
Popular conversions
- Hours to Minutes
- Minutes to Hours
- Minutes to Seconds
- Seconds to Minutes
- Hours to Seconds
- Seconds to Hours
- Days to Hours
- Hours to Days
- Weeks to Days
- Days to Weeks
- Milliseconds to Seconds
- Seconds to Milliseconds
- Years to Days
- Days to Years
- Months to Days
- Days to Months
- Weeks to Months
- Months to Weeks
- Years to Weeks
- Weeks to Years
- Months to Years
- Years to Months
- Days to Minutes
- Minutes to Days
- Years to Hours
- Hours to Years
- Microseconds to Milliseconds
- Milliseconds to Microseconds
- Nanoseconds to Milliseconds
- Nanoseconds to Seconds
- Decades to Years
- Centuries to Years
- Years to Seconds
- Days to Seconds
- Hours to Weeks
Questions people ask
How many seconds are in a day?
86 400 seconds: 24 hours × 60 minutes × 60 seconds.
How long is a month in days?
On average 30.436875 days in the Gregorian calendar. Real months have 28, 29, 30 or 31 days.
How many weeks are in a year?
About 52.18 weeks on average: 365.2425 days ÷ 7. A common year of 365 days has 52 weeks and 1 day.
Factors checked 19 October 2026.