Date Calculator
Date Calculator
Add, compare, and shift dates with calendar-accurate rules.
Result date
2026-08-04
Tuesday, August 4, 2026
Live
Calendar
Offset
Weekday
Tuesday
Calendar movement
+30 days
Applied interval
30 days
Rules
Add 30 days to 2026-07-05: 2026-08-04 (Tuesday, August 4, 2026). Components are applied in years, months, weeks, then days order.
Uses date-only UTC arithmetic. Month/year offsets clamp to the last valid day when needed.
Formula
Result date = Start date +/- interval; Date span = End date - Start date \Delta d = d_{\text{end}} - d_{\text{start}} - Choose add/subtract, exact difference, or workday mode.
- Calendar offsets apply years, months, weeks, then days and clamp invalid month-end dates.
- Difference mode can include or exclude the end date and reports exact calendar and total-day spans.
- Workday mode skips weekends plus the selected standard or custom holidays.
Example
Worked example: 2026-06-06 plus 30 days
- 1 Start date = 2026-06-06
- 2 Offset = +30
- 3 Result = 2026-07-06
The adjusted date is 2026-07-06.
How
- Choose Add / subtract, Difference, or Workdays.
- Enter the relevant dates and calendar interval or workday count.
- Set inclusive counting and business-day holiday rules when needed.
- Review the ISO date, natural-language date, exact span, and calendar movement.
Avoid
- Mixing inclusive and exclusive end-date counting.
- Assuming every organization follows the same holiday calendar.
- Expecting January 31 plus one month to remain on day 31.
- Typing an invalid calendar date or decimal interval.
FAQ
Can I subtract days?
Yes, enter a negative offset to move backward in time.
Does this support leap years?
Yes, date arithmetic follows real calendar rules including leap years.
Does this skip weekends?
Workdays mode skips weekends. It can also use standard observed US federal holidays and your custom closure dates.
Can I calculate the exact time between two dates?
Yes. Difference mode shows total days, exact years/months/days, weeks plus days, and business days.
How are month-end dates handled?
Month and year offsets clamp to the last valid day, so January 31 plus one month becomes February 28 or 29.
Switch
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