The objective of this article is to understand how we can use Power Automate aka Flow to calculate the due date for a task excluding holidays and weekends.
1. Create a SharePoint list Titled Work Progress Tracker using the default template ‘Work Progress Tracker’ as it has most of the columns needed for our demo. We will use this list to track the work items assigned to the team members.
Tip: While creating the list we used the title as WPT to shorten the url and changed the list title to Work Progress Tracker post creation.
2. Create a column to track the workdays assigned for a task. This will be used to calculate the Due Date excluding the weekends and holidays. The column will be created with the following details:
Name: Task Completion Workdays
Type: Number
Require that this column contains information: Yes
Number of decimal places: 0
Add to default view: Yes
3. Change the Start Date column in the list as a required column. If the item is created without the start date, the flow will fail. Hence we make this a required column.
4. Create a new list with the title Company Holiday List with the Blank list This will be used to track the company holidays that need to be excluded from the workdays for due date calculation.
5. Create a new column Date to track the Holiday date in the Company Holiday List with the following details.
6. Rename the Title column in the Company Holidays List to Holiday Description
4. Specify the desired name (we have named it ITHelpdesk Task DueDate Calculator) and under the triggers select When an item is created (SharePoint). This will trigger the flow as soon as an item is created our Work progress tracker
5. In the trigger specify the site URL and the list name as shown below. The list is the work progress tracker list we created earlier to track work tasks.
6. Initiate the following variables which will be used further in the flow for calculations.
a. Workdays – This will be used to keep a count of how many workdays have passed in our process to derive at a Duedate excluding the Holidays and Weekends.
i. Type: Integer
ii. Value: int(triggerOutputs()?['body/TaskDays'])
b. Counter – This will be used to keep a count on the number of loops needed in calculation of the Due date in the Do While loop further.
i. Type: Integer
ii. Value: 0
c. StartDate – This variable is used to capture the value of the StartDate field in the list and will be further used in calculating the due date
i. Type: String
ii. Value: formatDateTime(triggerOutputs()?['body/StartDate'],'yyyy-MM-dd')
d. DueDate – This variable will be used to store the value of the due date during the calculation in the Do While loop further.
i. Type: String
ii. Value: @{variables('StartDate')}
7. Add a Do Until control to loop the actions within, until the counter variable is equal to the variable workdays.
The purpose of this action is to create a loop to calculate working days, by excluding the weekends and company holidays. This is achieved by using the dayOfWeek expression and matching against the dates in the Company Holidays List.
Expression values:
Counter: variables('Counter')
Workdays: variables('Workdays')
Also change the limits in the Do until loop and set the count to blank which means this will be set to unlimited loops.
8. Add a Compose action in the Do until loop to increment the due date by a day.
Expression: addDays(Variables('DueDate'),1,'yyyy-MM-dd')
9. Add a Set variable action in the Do until loop to set the variable DueDate. This will be further used to filter weekends and holidays.
Expression: outputs('Compose_to_increment_StartDate')
10. Add a condition to filter the weekends. Expression: dayOfWeek(Variables('DueDate'))
11. If the DueDate matches our condition (it is not a Saturday or Sunday), it moves to the next calculation step. Here we add a Get Items action from SharePoint list Company Holidays List with a filter query Date field equals DueDate variable value.
Expression: Date eq '@{variables('DueDate')}'
This will give us an output if the DueDate value is a Company Holiday.
12. The next step is to add a compose action to calculate the length of the output from the Get Items action. This will help us calculate of the current DueDate is a holiday if the output is not Zero.
Expression: length(body('Get_items_Company_Holidays_List')?['value'])
13. In the next step we add the Condition action to filter the holidays. If the output of the previous step of getting items where Date field does not match the Due date variable, the output length would be 0. This means that the current DueDate value isn’t a holiday and ehnce will be counted as a working Day for the Task. We use this logic to filter out the holidays.
Expression: @outputs('Compose_to_get_matching_count_with_Holidays')
14. If the condition output is true (number of items in the Company Holiday List where Date equals Due Date is Zero), we increment the Counter Variable by 1
15. The Do Until loop will complete until the variable counter matches the variable workdays.
16. In the final step we update the DueDate in the Work Progress Tracker list for the current item using the SharePoint – update item action.
Expressions:
a. ID
i. Value: @{triggerOutputs()?['body/ID']}
b. Title
i. Value: @{triggerOutputs()?['body/Title']}
c. Start date
i. Value: @{triggerOutputs()?['body/StartDate']}
d. Task Completion WorkDays
i. Value: @{triggerOutputs()?['body/TaskDays']}
e. Due date
i. Value: @{variables('DueDate')}
As you can see in the example, we will calculate the Due date when start date is 1st April’21, with 5 days duration. Consider 2nd April’21 to be a holiday.
The day for 2nd April’21 being a Company Holiday has been skipped hence the counter stays as 0. Also the days 3rd April’21 and 4th April’21 are skipped as it’s a weekend. Hence the Counting the Business Days, the DueDate will be 9th April’21.
Start Date | Running Due Date | Counter | Skip (Yes/No) | Notes |
1st April 2021 | 2nd April 2021 | 0 | Yes | Company Holiday |
| 3rd April 2021 | 0 | Yes | Weekend |
| 4th April 2021 | 0 | Yes | Weekend |
| 5th April 2021 | 1 | No | Business Day |
| 6th April 2021 | 2 | No | Business Day |
| 7th April 2021 | 3 | No | Business Day |
| 8th April 2021 | 4 | No | Business Day |
| 9th April 2021 | 5 | No | Business Day |
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Hi,
Thank you for sharing the flow.
I have tried to create a flow taking this flow as a reference. My requirement is that I have a list that gets populated with content requests of different priorities. I want to calculate the due date based on the priority criteria and calendar days.
There seems to a problem in step 6a. Initializing the variable value with int(triggerOutputs()?['body/TaskDays']). It shows error:
Unable to process template language expressions in action 'Initialize_variable_WorkDays' inputs at line '0' and column '0': 'The template language function 'int' was invoked with a parameter that is not valid. The value cannot be converted to the target type.'.
I made the value 0 and tested it.
Another error in step 6c:
Unable to process template language expressions in action 'Initialize_variable_StartDate' inputs at line '0' and column '0': 'The template language function 'formatDateTime' expects its first parameter to be of type string. The provided value is of type 'Null'. Please see https://aka.ms/logicexpressions#formatdatetime for usage details.'.
Removed the format and tested with blank value.
Another error in step 7/8
Unable to process template language expressions in action 'Compose_IncrementStartDate' inputs at line '0' and column '0': 'In function 'addDays', the value provided for date time string '' was not valid. The datetime string must match ISO 8601 format.'.
Please check the flow once with these errors and help.
Thanks,
Ray
Please check the internal names for the columns created in steps 2 and 3.
In our case, we have used short field names and you might be using different field names.
Ref: Get SharePoint Column Internal Names
Hope this helps!
Thank you so much for writing this blog. I was struggling with the best way to process this logic.
I have gone through all the steps but I found an issue.
Step 6c - We create DueDate with no value
Step 8 - Compose to increment StartDate, but the variable in the instruction is DueDate:
addDays(Variables('DueDate'),1,'yyyy-MM-dd'). This results in an error as we cannot add days to a blank value.
ERROR:
InvalidTemplate. Unable to process template language expressions in action 'Compose_to_increment_StartDate' inputs at line '0' and column '0': 'In function 'addDays', the value provided for date time string '' was not valid. The datetime string must match ISO 8601 format.'.
I surmised that we should initalize the DueDate with the same expression as the StartDate, and this now works.
Thank you again.
Hi Fleur,
There was an issue in the Due Date step - we have fixed it and updated the post. Please re-check the steps and implement it.
Sorry for the inconvenience caused !
Regards,
Jasjit
Hi, can this workflow be used "When an item is created or modified"? I want to calculate the due date once the status is updated to "Submitted" not when the item is created. On step 6, what is "TaskDays" referring to as I don't see that column on any of the sharepoint lists? I'm also getting an error message in the Flow checker for the variable DueDate: "Actions in this flow may result in an infinite trigger loop. Please ensure you add appropriate conditional checks to prevent this flow from triggering itself."
You are most likely missing step 6(d) where we initiate DueDate variable.
And yes, you can use this flow for "When an item is created or modified".
Hope this helps!
Hi Reshma,
We had to update our blog. There was a mistake in the Due Date step. Sorry for the inconvenience caused.
Regards,
Jasjit