I have noticed a number of issues with DataSheet/Gantt View when using calculated columns, i will list others at the bottom, however my main concern here is my gantt chart not showing an end date for tasks when the end date is a calculated column.

As you can see in the image I have a "days" column, an "hours" column, a calculated "duration" column (which breaks the hours down into subsets of the day and then adds this to the day) and an "End Date" Column, which is simply [Start Date]+[Duration].

It seems that Sharepoint Online is reading my end date column as blank. (on a side not if i update a task while in the gantt view it will then draw out my bar correctly, however if i leave the page and come back, it will again act as if the end date is blank)

side issues i noticed

  1. I also noticed that though i have a duration column set to 2 decimal places it shows a number of decimal places. (again if i update the task item, this will then revert to 2 decimal places until i leave and return to the page)

  2. I also noticed that my calculated end date column shows as US date format though i am set to UK (and other columns show in UK format)

I have logged a support request with Microsoft, so I will update this with anything useful i learn from them

I am also considering using a workflow to copy the calculated End Date into a standard date column (though this will be a last resort workaround as i don't think you will see the updates until you exit the page and return)

Thanks in advance for any feedback

Gantt Chart

  • 2023 still does the same crap. not too useful. So I have to learn workflows...?
    – bob
    Jul 7, 2023 at 18:42

2 Answers 2


I have just got off the phone with Microsoft and it appears that calculated columns are not support in Gantt Chart views for tasks.

My workaround will be to run a workflow to copy the date of the calculated column into a normal date column.


Its 2019 and the issue is still persistent. I have created a calculated start/enddate field and even modified the formatting to meet the sites requirements. Yet, still nor bars - only my titles

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