Time Unit Table

The following table shows the most common time units and their durations.

UnitDefinition
millennium1,000 years
century100 years
decade10 years
year (average)365.242 days or 12 months
common year365 days or 12 months
leap year366 days or 12 months
quarter3 months
month28-31 days
January, March, May, July, August. October, December - 31 days
April, June, September, November - 30 days.
February - 29 days for leap year and 28 days for common year
week7 days
day24 hours or 1,440 minutes or 86,400 seconds
hour60 minutes or 3,600 seconds
minute60 seconds
secondbase unit
millisecond10-3 second
microsecond10-6 second
nanosecond10-9 second
picosecond10-12 second

SI Unit of Time

The SI unit of time is Second. Also, we can call it a base unit of time. We can easily observe seconds and count them. There are some more units of time such as milliseconds, microseconds, and nanoseconds. Those are smaller than the second. In addition, there are also some bigger time units like minutes, hours, days, weeks, months, and years.