When to use this tool
- Calculate due dates.
- Add business days to support deadlines.
- Move a date by weeks, months, or years.
Date math
Date calculator
Add or subtract calendar units, including business days, and copy the resulting date.
Result date
Sat Jul 04 2026
ISO
2026-07-03T16:00:00.000Z
Date Calculator: definition and examples
A date calculator applies a calendar interval to a starting date and returns the resulting date.
How to use it
- Choose a start date.
- Enter a positive or negative amount.
- Select the unit and copy the result.
Example
Adding 10 business days to a Monday skips weekends and lands two calendar weeks later.
Frequently asked questions
Can I subtract dates?
Yes. Enter a negative amount to subtract the selected unit.
How are month-end dates handled?
Month and year calculations follow date-fns calendar behavior for end-of-month dates.