# Excel WEEKDAY function

## Summary

The Excel WEEKDAY function returns a number representing the day of the week for a given date. The function can be configured to determine which day is considered the first day of the week, with Sunday as the default first day.
##### Syntax
```				```
=WEEKDAY(serial_number, [return_type])
```
```
• serial_number: The date for which the day of the week is required.
• return_type: [Optional] A number representing the day of week mapping scheme. Default is 1.
##### Return value
A number between 1 and 7, representing the day of the week.

## How to use

The WEEKDAY function is used to determine the day of the week for a given date. It accepts a date (serial_number) and an optional return_type, which specifies the numbering scheme for the days of the week.

Return Types and Their Day Mapping:

• `1 (Default):` 1 (Sunday) to 7 (Saturday)
• `2`: 1 (Monday) to 7 (Sunday)
• `3`: 0 (Monday) to 6 (Sunday)
• `11`: 1 (Monday) to 7 (Sunday)
• `12`: 1 (Tuesday) to 7 (Monday)
• `13`: 1 (Wednesday) to 7 (Tuesday)
• `14`: 1 (Thursday) to 7 (Wednesday)
• `15`: 1 (Friday) to 7 (Thursday)
• `16`: 1 (Saturday) to 7 (Friday)
• `17`: 1 (Sunday) to 7 (Saturday)

## Examples

##### Simple WEEKDAY
Identifying the Day of the Week:
```				```
=WEEKDAY("2021-01-01")
```
```
Returns 6, indicating that January 1, 2021, was a Friday.
##### WEEKDAY with Return Type
Customizing First Day of the Week:
```				```
=WEEKDAY("2021-01-01", 2)
```
```
Using return type 2, this formula returns 5, mapping January 1, 2021, to a Friday, with Monday as the first day of the week.
##### WEEKDAY and TODAY
Planning Based on Day of the Week:
```				```
=WEEKDAY(TODAY(), 3)
```
```
Calculates the day of the week for the current date, with Monday as 0 and Sunday as 6.