Find the date a given number of days, weeks, months or years before or after another date.
Runs entirely in your browser.
Add or Subtract Days, Weeks, Months or Years
- Start Date
- Operation
- Amount
- Unit
About Add or Subtract Days
Adding days and weeks is simple counting. Adding months and years is not, because the target month may be shorter than the starting one - so this clamps to the last valid day instead of rolling into the next month. Adding one month to 31 January gives 28 February, not 3 March.
That clamping is what almost everyone means by "a month later", and it is what spreadsheet and database date functions do too.
Other Date Tools
- Date Calculator — difference, arithmetic and age on one page
- Age Calculator — exact age and days to the next birthday
- Date Difference — the span between two dates
- Leap Year Checker — is a year a leap year, and why
- Day of the Week — weekday, day of year and ISO week
- Unix Timestamp — epoch seconds to and from a date
- Time Converter — seconds, minutes, hours, days, weeks