WEEK
Returns the week number for a given date.
Sample usage
WEEK(Date)
Syntax
The following syntax returns the week number from a Date value.
WEEK(date_expression )
The following syntax returns the week number from a compatibility mode Date value.
WEEK(X [,format_string ])
Parameters
date_expression- a Date & Time field or expression.X- a field or expression that evaluates to Text, Number, or compatibility mode Date.format_string- format forX. Optional ifXis correctly configured as a semantic date field.
Format strings for compatibility mode dates
Supported date functions accept the following input formats ifX is a Text field or expression, or compatibility mode Date:
BASIC: %Y/%m/%d-%H:%M:%SDEFAULT_DASH: %Y-%m-%d [%H:%M:%S]DEFAULT_SLASH: %Y/%m/%d [%H:%M:%S]DEFAULT_DECIMAL: %Y%m%d [%H:%M:%S]RFC_1123: for example, Sat, 24 May 2008 20:09:47 GMTRFC_3339: for example, 2008-05-24T20:09:47ZDECIMAL_DATE: same asDEFAULT_DECIMAL
Any validstrptime format is accepted.
Supported time functions accept the following input format ifX is a Number field or expression:
SECONDS: seconds since EpochMILLIS: milliseconds since EpochMICROS: microseconds since EpochNANOS: nanoseconds since EpochJULIAN_DATE: days since Epoch
Examples
| Example formula | Input | Output |
|---|---|---|
WEEK(Date) | Jan 1, 2019 | 1 |
WEEK(Date as Text, 'BASIC') | 2019/01/01-09:40:45 | 1 |
WEEK(Date as Number, 'SECONDS') | 1561784874 | 26 |
| 1562004058620 | 27 |
Notes
This function works with both compatibility mode dates andupgraded Date and Date & Time data types.
This function returns the week number since the start of year per the ISO 8601 standard.
Related resources
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Last updated 2026-02-19 UTC.