ExcelDateBeginner

WEEKDAY

Returns the day of the week as a number (1-7).

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=WEEKDAY(serial_number, [return_type])
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What the function does

Overview

Returns the day of the week as a number (1-7).

The WEEKDAY function identifies the day of the week for a specific date, returning an integer that maps to a specific day based on the ype argument. By default, it treats Sunday as 1 and Saturday as 7. For many business and scheduling workflows, using ype 2 (where Monday is 1 and Sunday is 7) is preferred as it aligns with ISO 8601 standards and standard work weeks. If the umber is not a valid Excel date—such as text that isn't recognized or a number outside the supported range (0 to 2,958,465)—the function will return an error. This function is often nested within IF or CHOOSE functions to trigger conditional logic for weekend processing or to generate human-readable day names.

Quick reference

Syntax

=WEEKDAY(serial_number, [return_type])

Inputs

Arguments

serial_numberDate to check
Example: A2
return_type (optional)1=Sun-Sat (default), 2=Mon-Sun
Example: 2

Formula patterns

Examples

1

Identify Weekends

=IF(WEEKDAY(A2, 2) > 5, "Weekend", "Workday")
schedulingconditional logic
2

Calculate Next Monday

=A2 + (8 - WEEKDAY(A2, 2))
date mathplanning
3

Convert Date to Business Day Index

=WEEKDAY(A2, 2)
data cleaninganalysis

Avoid these issues

Common Errors

1

#VALUE!

Cause: The serial_number is text that cannot be parsed as a date, or the return_type is non-numeric.

Fix: Ensure the input cell contains a valid date or use the DATEVALUE function to convert text strings into proper Excel dates.

2

#NUM!

Cause: The return_type is outside the allowed range (1-3, 11-17) or the serial_number is a negative number.

Fix: Check that the return_type argument is valid and ensure the date is after 1/1/1900.

Platform support

Compatibility

Excel 2007+Excel-first

Source: Microsoft Support

Common questions

Frequently Asked Questions

Returns the day of the week as a number (1-7).

umber: Date to check ype: 1=Sun-Sat (default), 2=Mon-Sun

#VALUE!: Ensure the input cell contains a valid date or use the DATEVALUE function to convert text strings into proper Excel dates. #NUM!: Check that the ype argument is valid and ensure the date is after 1/1/1900.