How to Use WEEKDAY Function

The WEEKDAY Function returns the day of the week with the date you specified.


= WEEKDAY(serial_number,[return_type])


  • Serial_number is required. A sequential number that represents the date you are looking for. Serial number should be a date in Microsoft Excel format, the function will return to an error when it is in a wrong format, such as text format.
  • Return_type is optional. A number that determines the returned value, please refer to the following table for details.


By default, Microsoft Excel uses January 1, 1900 as serial number 1. If a serial number or return type is out of the range, the result will return "#NUM!" error.

Example: To determine the number of the day in the week

There are many different ways to count the days in a week, for example, people count Sunday as the first day of week in some areas, but people can also count Monday as the first day of the week in some other areas.

January 18, 2016 is a Friday, when counting Sunday as the first day, the result will return 6, and it the 6th day of the week. However, when counting Monday as the first day, the result will return 5, and it is the fifth day of the week.

Download: WEEKDAY Function

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