Syntax
WEEKDAY(serial_number, [return_type])
| Parameter | Description |
|---|---|
| serial_number | Parameter of the WEEKDAY function. |
| [return_type] | (Optional.) Parameter of the WEEKDAY function. |
Examples
Default day of week
Formula
=WEEKDAY("2026-04-09")
Returns 5 (Thursday) using the default system where Sunday=1, Monday=2, ..., Saturday=7.
Monday-start system
Formula
=WEEKDAY("2026-04-09", 2)
Returns 4 (Thursday) using return_type 2 where Monday=1, Tuesday=2, ..., Sunday=7.
Identify weekends
Formula
=IF(WEEKDAY(A1,2)>5, "Weekend", "Weekday")
Returns "Weekend" for Saturday (6) and Sunday (7) using the Monday=1 system. Clean way to classify any date.
Common Errors
#VALUE!
Occurs when the date argument is not a valid date or the return_type is not a recognized number (1, 2, 3, 11-17).
#NUM!
Occurs when the date serial number is out of range.
Tips
Return type options
Type 1 (default): Sun=1 to Sat=7. Type 2: Mon=1 to Sun=7. Type 3: Mon=0 to Sun=6. Types 11-17 start from different days of the week.
Weekend check shortcut
With return_type=2: =WEEKDAY(date,2)>5 catches Saturday and Sunday. Much cleaner than checking for 1 and 7 in the default system.
Use for conditional formatting
Apply =WEEKDAY(A1,2)>5 as a conditional formatting rule to highlight weekend dates automatically in a date column.
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