Popular time conversions
Time & duration units
The second is the SI base unit of time, defined by the caesium-133 atom. Months and years vary in length, so this converter uses Gregorian averages: a year of 365.2425 days and a month of 30.436875 days. For exact calendar spans between two dates, use the date calculator.
| Unit | Symbol | In seconds | Definition |
|---|---|---|---|
| Nanosecond | ns | 1 × 10⁻⁹ s | |
| Microsecond | µs | 0.000001 s | |
| Millisecond | ms | 0.001 s | One thousandth of a second. |
| Second | s | 1 s | The SI base unit of time, defined by 9,192,631,770 cycles of the caesium-133 hyperfine transition. |
| Minute | min | 60 s | Sixty seconds. |
| Hour | h | 3,600 s | Sixty minutes, or 3,600 seconds. |
| Day | d | 86,400 s | Twenty-four hours, or 86,400 seconds. |
| Week | wk | 604,800 s | Seven days. |
| Fortnight | fortnight | 1,209,600 s | Fourteen days. |
| Month | mo | 2,629,746 s | An average Gregorian month of 30.436875 days (one twelfth of 365.2425 days). |
| Year | yr | 31,556,952 s | An average Gregorian year of 365.2425 days. |
| Decade | decade | 315,569,520 s | Ten years. |
| Century | century | 3,155,695,200 s | One hundred years. |
| Millennium | millennium | 31,556,952,000 s | One thousand years. |
Calculate with time
The smart calculator does arithmetic across time units and picks a sensible unit for the answer. Try 2 h 45 min + 90 min.
Questions and answers
Which time units can I convert?
All 14: nanoseconds, microseconds, milliseconds, seconds, minutes, hours, days, weeks, fortnights, months, years, decades, centuries, millennia.
What is the SI unit of time?
This converter uses the second (s) as its base unit. The second is the SI base unit of time, defined by the caesium-133 atom. Months and years vary in length, so this converter uses Gregorian averages: a year of 365.2425 days and a month of 30.436875 days. For exact calendar spans between two dates, use the date calculator.
How long is a month in this converter?
Months and years change length, so unit conversion uses Gregorian averages: a year of 365.2425 days and a month of 30.436875 days. For exact spans between two calendar dates, use the date calculator.
How precise are the results?
Factors are the exact legal definitions where one exists (an inch is exactly 2.54 cm, a pound exactly 0.45359237 kg). Results show 10 significant digits by default; the precision menu offers 4 to 15.
Does the time converter work offline?
Yes. ConvertEasy is a progressive web app: after your first visit it keeps working with no connection, and you can install it to your home screen from the browser menu.