Calendar Date Math
Add or subtract calendar days from a selected date. Enter a start date and signed number of days: positive moves forward and negative moves backward. Weekends and holidays are included.
Use the tool
Enter your values, then run it. The result is generated in your browser.
Result
Calculated
How to use Calendar Date Math
- Choose a starting date.
- Use positive days for the future and negative days for the past.
- Check special rules for business days or holidays if relevant.
Formula and assumptions
Result date = start date shifted by the signed number of calendar days.
For legal deadlines or business-day schedules, confirm jurisdiction-specific rules and holiday calendars.
Frequently asked questions
Are weekends counted?
Yes, this tool counts calendar days.
How do I subtract days?
Enter a negative value.
Are holidays excluded?
No, holidays are included as ordinary calendar dates.
About this tool
Enter a start date and signed number of days: positive moves forward and negative moves backward. Weekends and holidays are included.
No account is required. The tool runs in this browser and this starter build has no form-submission backend. See the method and assumptions before relying on estimates.