Calendar Date Calculator
Add or subtract days from a date, or calculate the calendar interval between two dates.
Calendar Calculator
Use this calculator to easily add or subtract days, weeks, months, or years to any date, or to find the number of days between two dates. Supports calendar years, months, weeks, and is mobile friendly.
ABOUT THIS TOOL
Calendar Date Calculator
Add or subtract calendar periods from a date, or count the days between two dates. Month-end clamping and leap years are handled explicitly.
How to use this tool
- Choose date arithmetic or date difference.
- Enter the date and interval.
- Calculate and copy the resulting date or duration.
Examples
- Add one month to January 31 and clamp to February month-end.
- Count days between two deadlines with optional inclusive boundaries.
Frequently asked questions
Are both boundary dates counted?
Enable the inclusive option when both the starting and ending dates should count.