I am using MS Project 2016. Summary calculations for duration are all correct, but SOME of the summary calculations for Work are double or quadruple what they should be, as if it's including subtotals (subtasks) in the calculation. Where do I look for the culprit

  • MSP2013 and on has a bug in calculating graphs. It does not see decimal point eg 8.5hrs is calculated as 85hrs for the graph. Try a simple test to prove it. In this instance do not think it is relevant but worth noting. Cheers
    – Brian H
    Commented Oct 18, 2018 at 7:33
  • You can not start a task before the start date of any summary task involved.
    – Greasle
    Commented Mar 10, 2020 at 8:43

6 Answers 6


Whenever I see any calculation problems on summary tasks I check to see if the summary task in question may have had constraints set by accident, actual values of any kind set, resources applied to it, etc. Summary tasks should not have actuals, resources, any manually entered work values, etc. I've seen these kinds of things carry forward if the task was promoted to a summary task after data had been entered on it. If I was writing that code I'd do the same thing.

Also we have noticed Project is not always happy when resources are added to tasks that have actuals recorded.

Sometimes we have to record all the data from the task in question, drop it, and re-create the task. Not fun and it's a last resort of course.

Manual scheduling & dependencies might come into play if leveling is being used and I'd have to do some experimentation with that.

Ummm, the other gotcha is filters, right? ... Sometimes someone has copied stuff in there and it's filtered out and you just miss that. Worth a try to kill all the filters and expand all the tasks if you haven't done that ... Been there!


I outdent the summary task and add a new summary task. Then I indent the lower task and this works.


When you assign resources at both sub tasks and summary level, MPP adds the effort for both. This leads to duplication of effort. Only load resources at sub task levels.


One of the great things about the most recent versions of MS Project is that they "auto schedule" feature actually works. In past versions, PM's had to manually schedule many of their tasks to make MS Project work properly.

First, check to make sure you're auto-scheduling as much as possible. Second, for the tasks you are manually scheduling, check out your task information to make sure everything is accurate. Third, make sure your predecessors/successors are set-up properly. Sometimes, folks will accidentally set a major task as a predecessor of a another major task's subtask.

Please let me know if this helps.


I tried all this. Nothing worked. In the end, I out-dented all the daughter tasks, deleted the summary task, inserted a new summary task (same details), indented the daughter tasks, and voila !


A summary's task Work field is showing incorrect hours? I had this issue before, and found it was due to a resource assigned to the summary task. Deleting the resource assignment from the summary task resolved the issue.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.