How to calculate workdays with PowerApps
In some use cases you have to calculate the number of working days between a start date and an end date.
Because of there is no proper function available, you have to do calculate it on your own.
My sample App consists of
two date pickers for selecting the date range (datFrom and datTo)
a button to start the calculation
a label to display the result
My algorithm is like that:
Number of days
Calculate the number of days between the start date and the end date. Then add 1 to include the start date.
//Get Date Difference
UpdateContext(
{
ctxNumberOfDays: DateDiff(
datFrom.SelectedDate;
datTo.SelectedDate
)+1
}
);;
Weekends
Now calculate the number of days on a weekend.
Determine the number of weeks:
//Calculate Number of Weeks
UpdateContext(
{
ctxNumberOfWeeks: RoundDown((ctxNumberOfDays / 7);0)
}
);;
Calculate the rest because 10 Days are one week and 3 Days:
//Calculate Days on top of full weeks: 10 Days: 1 Week, 3 Days Rest
UpdateContext(
{
ctxDaysRest: Mod(ctxNumberOfDays;7)
}
);;
If we have one weeks, we can assume that we have 1 weekend.
But if the Weekday of datStart + 3 days (example above) are greater than the greates Weekday+1 (Saturday=7, The following Sunday would be 8 so everything greater than 8 means that we have walked over a Monday), we have to increase the number of weekends by 1.
More to Dates and Times: https://docs.microsoft.com/de-de/powerapps/maker/canvas-apps/functions/function-datetime-parts
Important:
This only works with Sunday as the first day of week (Default in Powerapps!) and Monday as the first workingday.
//Check if the Rest is on a weekend. If so, then we have one more weekend
If(
Weekday(datFrom.SelectedDate) + ctxDaysRest > 8;
UpdateContext({ctxWeekends: ctxNumberOfWeeks + 1});
UpdateContext({ctxWeekends: ctxNumberOfWeeks})
);;
Now we have to calculate the number of weekend days. Because of one weekend are two days, we multiplicate the number of weekends by 2:
1
2
//Calculate Weekend days
UpdateContext({ctxWeekendDays: ctxWeekends * 2});;
Important:
In a real world scenario you have to prevent the user from selecting a weekend day and show a message like “You may not select a week end day”.
Public Holidays
Last but not least we have to check if there are any public holidays. In this sample I have created a simple collection of dates. You are free to put this data into a SharePoint list and filter them by the current year.
With CountIf I’m able to count how many entries of my holiday collection fits the condition to be greater or equal than the start date and less or equal than the end date:
ClearCollect(PublicHolidays;{Date:Date(2019;10;18)});;
UpdateContext(
{
ctxNumberOfPublicHolidays:
CountIf(
PublicHolidays;
Date>=datFrom.SelectedDate;
Date<=datTo.SelectedDate
)
}
);;
Final
To get the final result, you have to Take the complete number days – weekend days – public holidays:
//Calculate result
UpdateContext(
{
ctxWorkingDays: ctxNumberOfDays - ctxWeekendDays - ctxNumberOfPublicHolidays}
);;
That’s it!
I hope you will find this useful.
