Add or Subtract Days
Add or subtract days from a date and show the resulting weekday.
● Processed locally in your browser unless the page says otherwise.
How dates are handled
How to add or subtract days from a date
This date calculator adds days to a starting date or subtracts days from it, then shows the resulting date and weekday. It is useful for deadlines, delivery dates, travel planning, warranty periods, project schedules, and payment dates.
Be careful whether your situation counts calendar days or business days, and whether the starting date is included. This tool uses general calendar-day logic.
Formula or logic
- Result date = Start date + number of days
- Backward calculation: Result date = Start date - number of days
- Calendar days usually include weekends and holidays
Example
If you add 30 days to August 7, 2026, the result is 30 calendar days later. If your rule uses business days, weekends and holidays may need to be excluded.
Common questions
Are calendar days and business days the same?
No. Calendar days include weekends and holidays; business days usually exclude non-working days.
Should the start date count as day one?
Rules vary by use case. This tool gives general date arithmetic, so formal deadlines should be checked against the relevant rule.
Can this be used for due dates?
Yes for quick estimates, but legal, contract, or financial due dates should be reviewed carefully.