Separating weekends and weekdays is a common task in Excel. For example, when you have to build an automatic calendar.
The function WEEKDAY
This function returns a value between 1 and 7 corresponding to the value of the day of the week.
This function is very, very, VERY useful for creating a test in a IF function or for a conditional formatting.
Explanation of the second parameter
The second parameter is optional but very useful if you are NOT in USA or Canada.
In USA, the first day of the week is Sunday. So, if you don't specify this parameter 1 = Sunday.
But for most countries in the world, the first day of the week is Monday. This is why it is important to indicate the value of this parameter in function of your localization.
Basic value for the second parameter
For all the versions of Excel, the value for the second parameter could be
- 1 - The week starts on Sunday (value 1) and finishes on Monday (value 7). It's the default value (or empty)
- 2 - The week starts on Monday (1) and finishes on Sunday (7)
- 3 - The week starts on Sunday (0) and finishes on Monday (6)
The screenshot below displays the different results returned for the same date (01/01/2018) in function of the second parameter chosen.
How to test if a date is a weekend?
If you want to check if a date is a weekend or not, you can write this simple test with the WEEKDAY function.
With this test, if the day of the week is 6 or 7, it's a weekend 😃
If you don't want to specify the second parameter, Sunday = 1 and Saturday = 7. So the test is a little more complex to write.
To highlight the day of the weekend in RED you can use exactly the same formula inside a conditional formatting rule.
- Copy your formula WEEKDAY
- Select all the cells of your document
- Open the menu Home>Conditional Formatting>Manage Rules>New Rules
- Select the option Use a formula to determine which cells to format
- Paste the formula
- Change the format
Now, when the day of your dates is a Saturday or Sunday, the background of cells is red.
Add only weekdays
Another very useful week function in Excel it's the WORKDAY function.
When you add days to a date, Excel will always include the weekend. For example, when you add 4 days to the 21/04/2021 (Wednesday), the result is Sunday the 25th
But, if you want to add 4 weekdays to your original date, WORKDAY will return Tuesday the 27th. Saturday and Sunday have been not included. This function is very useful to build a task calendar or a Gantt Chart.
Number of weekdays between 2 dates
The third-week function in Excel is the function NETWORDAYS. It returns the number of weekdays between 2 dates.