Function Reference: ISOWEEKNUM
| Syntax | ||
| =ISOWEEKNUM(date) | ||
| Syntax | ||
| Returns the week number for a date according to the ISO8601 standard for calculation. | ||
| Arguments | ||
| Name | Type | Description |
| date | number | A constant, reference or nested expression which provides the serial date number for which the week number is to be calculated. |
| Return Values | ||
| Type | Specific Value | Description |
| number | The week number in which the date falls. | |
| error | #VALUE! | If value passed to date is not a number and cannot be coerced to a number. |
| arror | #NUM! | If the value passed to date is outside the he range allowed. 1900 date system: 0 to 2,958,465 1904 date system: 0 to 2,957003 |
| error | Any errors referenced by arguments are returned due to propagation of error values. | |
| Notes / Comments / Advice / Warnings | ||
| Note: | This function was added to Excel in Excel 2016. | |
| Comment: | ISOWEEKNUM returns week numbers that will always have 7 days. Three years will have 52 weeks and the fourth, 53 weeks. Weeks at the beginning and ending of a year calculated with this method will commonly have days from the previous or following year included in them. | |
| Advice: | We recommend using this function rather than WEEKNUM for calculating week numbers, as it is standardised and will avoid any confusion in B2B transaction. | |
| Examples: | Open / download sample workbook: ISOWEEKNUM, WEEKNUM.xlsx | |
| Further Info: | Information on ISO8601 can be found at the International Standards Organisation and on Wikipedia. | |