How to add days to a date
Here it is with your numbers:
- November 9, 2026 to November 30, 2026: 21 days (69 to go).
- November 30, 2026 to December 31, 2026: 31 days (38 to go).
- December 31, 2026 to January 31, 2027: 31 days (7 to go).
- January 31, 2027 to February 7, 2027: 7 days.
- You land on Sunday, February 7, 2027.
It means 90 days after November 9, 2026 is Sunday, February 7, 2027.
The start date is day 0, so 1 day after a Friday is the Saturday. A week is 7 days. To go back in time, choose Subtract.
Source Microsoft Support · Add or subtract dates ↗
Adding months and years
Months keep the day of the month: 5 months before September 15, 2019 is April 15, 2019. When the new month is too short for that day, we use its last day: January 31 plus 1 month is February 28 (February 29 in a leap year). Years work the same way, so February 29, 2024 plus 1 year is February 28, 2025.
Source Microsoft Support · EDATE function ↗
Business days and federal holidays
Business days are Monday to Friday. The start day isn’t counted, so 1 business day after a Friday is the Monday. Set Federal holidays to “Skip” to also pass over the 11 US federal holidays on the days they are observed: a holiday on a Saturday is observed the Friday before, and one on a Sunday the Monday after. We count them from 2021, when Juneteenth was added. State holidays and your employer’s own days off are not taken out.
Source Microsoft Support · WORKDAY function ↗OPM · Federal holidays ↗
| Federal holiday 2026 | Observed |
|---|---|
| New Year's Day | Thu, January 1 |
| Birthday of Martin Luther King, Jr. | Mon, January 19 |
| Washington's Birthday | Mon, February 16 |
| Memorial Day | Mon, May 25 |
| Juneteenth National Independence Day | Fri, June 19 |
| Independence Day | Fri, July 3 |
| Labor Day | Mon, September 7 |
| Columbus Day | Mon, October 12 |
| Veterans Day | Wed, November 11 |
| Thanksgiving Day | Thu, November 26 |
| Christmas Day | Fri, December 25 |
Add or subtract days examples
| Question | Answer |
|---|---|
| November 6, 2026 + 90 days | February 4, 2027 |
| January 31, 2026 + 1 month | February 28, 2026 |
| September 15, 2019 − 5 months | April 15, 2019 |
| February 29, 2024 + 1 year | February 28, 2025 |
FAQs
What is the date 90 days from today?
Leave the start date empty and enter 90. From November 6, 2026, 90 days later is Thursday, February 4, 2027. Today counts as day 0, so tomorrow is 1 day from today.
How to count 30 days from today?
Start counting with tomorrow as day 1. 30 days after November 6, 2026 is Sunday, December 6, 2026: 24 days to the end of November, then 6 more.
How to add days to a date in Excel?
Put the date in A2 and the number of days in B2, then use =A2+B2. Use a negative number to go back in time.
Is 90 days equal to 3 months?
Not exactly. Three months is 89 to 92 days, depending on the months: 3 months after November 6, 2026 is February 6, 2027, which is 92 days. Excel’s EDATE adds months the same way, keeping the day of the month.
How do I add business days to a date in Excel?
Use =WORKDAY(start_date, days, holidays). It skips Saturdays, Sundays and any holiday dates you list. Microsoft’s example: 151 workdays from October 1, 2008 is April 30, 2009.
Sources
- Microsoft Support: Add or subtract dates
- Microsoft Support: EDATE function
- Microsoft Support: WORKDAY function
- OPM: Federal holidays