How it works
Pick a start date, choose to add or subtract, enter a number, and select the unit (days, weeks, months, or years). The calculator instantly shows the resulting date, accounting for leap years and varying month lengths.
When adding months, if the resulting day exceeds the month's length (e.g., Jan 31 + 1 month), the date rolls to the last day of the target month (Feb 28 or 29).
FAQ
What happens when adding months to Jan 31?
Jan 31 + 1 month = Feb 28 (or Feb 29 in a leap year). The date adjusts to the last valid day of the target month.
Can I add negative numbers?
Use the "Subtract" option instead. The amount should always be a positive number.