Date & Time
Excel 2013
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=ISOWEEKNUM()
Returns number of the ISO week number of the year for a given date.
Applies To:
Excel for Microsoft 365Excel for Microsoft 365 for MacExcel 2024Excel 2024 for MacExcel 2021Excel 2021 for MacExcel 2019Excel 2016
=ISOWEEKNUM(date)
Hover argument names in the table for details.
Output typeNumber
Popularity20 / 100
VolatileNo
Dynamic ArrayNo
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◧ Arguments
| Argument | Type | Required | Description |
|---|---|---|---|
date |
Date | Required | Date is the date-time code used by Excel for date and time calculation. |
▣ Examples
▦ Data
| Cell | Value |
|---|---|
A2 |
Date |
A3 |
3/9/2012 |
A4 |
Date |
A5 |
3/9/2012 |
Number of the week in the year that 3/9/2012 occurs, based on weeks beginning on the default, Monday (10).
=ISOWEEKNUM(A2)
Result:
10
§ Remarks
- Microsoft Excel stores dates as sequential numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900.
- If the date argument is not a valid number, ISOWEEKNUM returns the #NUM! error value.
- If the date argument is not a valid date type, ISOWEEKNUM returns the #VALUE! error value.
✦ Tips
- Microsoft Excel stores dates as sequential numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900.
⚠ Common Errors
#NUM!
If the date argument is not a valid number, ISOWEEKNUM returns the #NUM! error value.
Fix: یک شماره سریال تاریخ معتبر یا سلول حاوی تاریخ وارد کنید.
#VALUE!
If the date argument is not a valid date type, ISOWEEKNUM returns the #VALUE! error value.
Fix: Use a real date instead of text
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