Worked example. Change the dates to calculate your own.
November 12, 2026
- Starting date
- October 1, 2026
- Calendar days moved
- 42
Adds seven calendar days per week. A negative number moves backward. The resulting weekday is the same as the starting weekday.
Dates stay in this page. No account, uploads or server calculation.
How this calculation works
Each week is seven calendar days. The tool moves the date by seven times the whole number you enter, with negative numbers moving backward. The weekday stays the same. Supported dates use years 1000 through 9999.
A worked example
Six weeks after Thursday, October 1, 2026 is Thursday, November 12. One week before it is September 24. Four weeks after January 31, 2026 is February 28, while adding one calendar month follows the month tool's clamping rule.
A week offset preserves the weekday
Each entered week is exactly seven calendar days. Four weeks is not always one calendar month.
| Starting date and offset | Result |
|---|---|
| October 1, 2026 plus 6 weeks | November 12, 2026. Both are Thursdays. |
| October 1, 2026 plus -1 week | September 24, 2026. |
| January 1, 2027 plus 0 weeks | January 1, 2027. |
| January 1, 2027 plus 4 weeks | January 29, 2027, not February 1. |
Enter your dates
Enter the start date and a whole number of weeks, then Calculate. Use a negative number to move backward. Use Add months when your plan follows calendar months.
Keep your next date in view
Keep the meeting or preparation date you calculated in Daymark. Add a countdown and the details you will need before it.
Get Daymark freeTwo active countdowns free. iOS 18 or iPadOS 18 or later. Apple Watch companion requires watchOS 11 or later.