Checked 15 October 2026. What was checked. How these pages are maintained.
How the date is moved
Days and weeks add a fixed number of midnights. Months and years keep the day of the month when they can. If you add one month to January 31, many calendars land on February 28 (or 29 in a leap year). This page follows that common rule.
Use it for “what day is 90 days from today,” a 14-day return window, or 6 months after a start date. The start date defaults to today. It does not skip weekends or holidays. For a count of weekdays between two dates, use the days-between calculator.
Examples: 30 days is always 30 midnights. 1 month from 31 January is the last day of February. 1 year from 29 February is 28 February in a common year.
Worked example
19 September 2026 plus 90 days is 18 December 2026. Plus 6 months is 19 March 2027 (the same day-of-month when it exists). Minus 14 days is 5 September 2026.
Insurance cancellation windows and some visas count calendar days, not business days. “90 days” from a Saturday still lands on a calendar date, even if offices are closed. Confirm whether the rule includes the start day.
Thirty midnights is not one month
Adding 45 days to 30 September 2026 lands on 14 November 2026. September 30 plus 31 days is October 31, and 14 more days is November 14. Adding one month to 31 January 2026 lands on 28 February 2026, because 2026 is not a leap year and this page keeps the day of the month only when that day exists. It does not spill into March. Adding one year to 29 February 2024 lands on 28 February 2025 for the same reason. Thirty days is always 30 midnights. One month is whatever the calendar says that month is.
The direction control subtracts instead of adding. Forty-five days before 30 September 2026 is 16 August 2026. Weeks are exact groups of 7 days. A result line also shows how many calendar days you actually moved, which is the check when a month-add looks longer or shorter than 30.
Deadlines that are not calendar days
A 10-day notice that excludes weekends and holidays is not 10 in the days box. This page counts Saturday and Sunday. It will not drop Canada Day or a provincial holiday. Count those on a calendar, or count weekdays with the days between dates calculator and still check the holiday list yourself. Whether the start day counts is a rule of the office that set the deadline. This page does not include the start day in a same-day sense: adding 1 day moves you to tomorrow. Insurance, visa, and court windows differ on that point. The date you type stays in the browser.
Common questions
What date is 90 days from today?
Leave the start date as today, set amount to 90 and unit to days, then Find date. The weekday is in the result.
Does 1 month always mean 30 days?
No. One month follows the calendar. 30 days is always 30 midnights. Pick the unit you mean.
Does this skip weekends?
No. Saturday and Sunday count. A 10-day notice that must be business days needs you to count those yourself.
What about time zones?
This page uses your computer’s local calendar date only.