The WEEKNUM() function returns the week number of a given date, as a numeric value (1, 2, 3, …), where the week starts on Sunday and week 1 is the one that contains January 1st.
Function name :
WEEKNUM()
Syntax
WEEKNUM(date)ℹ Calling function parameters in TimeTonic:
- $field_name = field (link, linked table column, number, selection, formula, text...).
- "free text" = free text to be added between quotation marks.
- do not use quotation marks for numbers.
Parameters
| Parameter | Description |
|---|---|
date |
Date for which to calculate the week number. |
Example
WEEKNUM(2026-1-10)Result: 2
January 10, 2026 falls in the 2nd week of the year according to this calculation method.
Notes
- The week starts on Sunday
- Week 1 is the one that contains January 1st
Works with all available formats of the date column.
Return type
The function returns a number representing the week number.
The output type format of the result can be configured in the output field options of the formula editor. For more details, see Output format options in the Formula column article.
Function comparison:
| Function | Start of week | Definition of week 1 |
|---|---|---|
| WEEKNUM(date) | Sunday | Week containing January 1st |
| ISO_WEEKNUM(date) | Monday | Week containing the first Thursday of the year |
The choice between WEEKNUM() and ISO_WEEKNUM() depends on the business context (internal planning, ISO standards, rounds, reporting)