Date Calculator
About this tool
Find the number of calendar days between two dates, or add or subtract a period from a chosen date. Inclusive counting can include both the first and last date when required.
How to use
- Calculate the difference between two dates
- Add or subtract days, weeks, months, or years
- Optionally count both the first and last date
- Show the weekday of the result
- Quickly select today
- Choose a calculation: Select the difference between two dates or add and subtract a period.
- Enter the dates: Choose the date or dates required for the calculation.
- Calculate: View the number of days or the resulting date.
Examples
- Calculate a notice period
- Find a project due date
- Count the number of days since an event
- Check a period that includes both the start and end dates
Limitations
- When a month does not contain the original day number, the result uses the last valid day of that month
- The tool counts calendar days and does not automatically exclude weekends or holidays
- The entered values and calculations are processed directly in your browser and are not sent to a server.
FAQ
- What is inclusive counting?
- When enabled, both the start and end dates count as full days in the difference.
- How are months added?
- If the target month has fewer days, the result uses its last valid day. For example, one month after January 31 is the last day of February.
- Does the tool calculate business days?
- No. It counts calendar days and does not automatically exclude weekends or public holidays.