Time Calculator

You can "add" or "subtract" two time values with this calculator. If you are looking to add or subtract some time from a date, please use the date calculator. Please provide the values in the fields above the "=". Then click the "Calculate" button to calculate. When entering, you can leave some fields blank. These fields will be taken as 0 by default.

Related: time zone calculator

Day Hour Minute Second
=


Reference

Like numbers, time can be added or subtracted. However due to the definitions, time can not be simply added or subtracted like normal decimal numbers. The following are the definitions of the common time units.

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
Jan., Mar., May, Jul., Aug. Oct., Dec.—31 days
Apr., Jun., Sep., Nov.—30 days.
Feb.—28 days for common year and 29 days for leap 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