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WEEKDAY Function
Summary
The WEEKDAY function in Excel returns a number representing the day of the week for a given date. By default, it assigns 1 to Sunday through 7 to Saturday, but offers flexible numbering systems via the return_type parameter for various analytical needs.
Syntax
WEEKDAY(serial_number,[return_type])Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| serial_number | Date/Serial |
Yes | The date as a serial number, DATE function result, or cell reference containing a date |
| return_type | Number |
No | Number from 1-17 specifying the return value format (omitted uses type 1) |
Using the WEEKDAY Function
WEEKDAY converts dates into their corresponding day-of-week numbers, crucial for scheduling analysis, workweek calculations, weekend detection, and creating date-based conditional logic in reports and dashboards.
Common WEEKDAY Examples
Default Weekday Numbering
=WEEKDAY(DATE(2023,12,25))Returns 1 for Christmas Day (Monday) using default Sunday=1 system
Workweek Numbering (Mon=1)
=WEEKDAY("1/15/2024",2)Returns 2 for Tuesday using Monday=1 through Sunday=7 system (result: 2)
Conditional Weekend Check
=IF(WEEKDAY(A2,2)>5,"Weekend","Weekday")Classifies dates in A2 as Weekend or Weekday using Monday=1 system
Frequently Asked Questions
Common Errors and Solutions
#NUM! error
Cause: return_type outside valid range 1-17
Solution: Use return_type values from 1 to 17 only
#VALUE! error
Cause: serial_number is text instead of date
Solution: Convert text to date using DATEVALUE or enter as proper date
#NUM! error
Cause: serial_number out of Excel date range
Solution: Ensure date falls between 1/1/1900 and 12/31/9999
Notes
- Excel stores January 1, 1900 as serial number 1
- return_type 11 matches return_type 2 exactly
- Use with MOD and other date functions for advanced analysis
- Essential companion to DATE, TODAY, and NOW functions
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in:
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+