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.
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.
| Unit | Definition |
| millennium | 1,000 years |
| century | 100 years |
| decade | 10 years |
| year (average) | 365.242 days or 12 months |
| common year | 365 days or 12 months |
| leap year | 366 days or 12 months |
| quarter | 3 months |
| month | 28-31 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 |
| week | 7 days |
| day | 24 hours or 1,440 minutes or 86,400 seconds |
| hour | 60 minutes or 3,600 seconds |
| minute | 60 seconds |
| second | base unit |
| millisecond | 10-3 second |
| microsecond | 10-6 second |
| nanosecond | 10-9 second |
| picosecond | 10-12 second |
