In MS Project, how can I apply a uniform scale to all durations? For instance if my project was allowed to be done in twice as much time, how would I double the duration of all tasks?

  • I am keen to understand why you would want to do this. You should plan based on how long tasks will take, not how long you have been allocated, so just because you have more time, why do you need to use it? - Unless you want to reduce your resource allocation to 50% of the time that was previously available! (Which may also be the answer that you need.)
    – Iain9688
    Jul 15, 2021 at 15:43

2 Answers 2


One way to do this without needing to save the file in an XML format or write any scripts would be to do the following:

  1. Hide all of the summary tasks
  2. Select header of the remaining duration column (this will select the entire column) Use ctrl + c to copy it to your clipboard

copied column

  1. Open an Excel worksheet and paste the remaining duration data in there.
  2. remove the duration label from the cells so you just have the duration number. Then use a excel formula to take the value of each cell and double it.


  1. copy the doubled values and paste back into the remaining duration column in MS Project.

NOTE - If your tasks contain resource assignments, you want to be aware of the task Type (Fixed Work/Fixed Duration) when editing durations. Changing the duration of a task when the Type is set to Fixed Duration will change the amount of work assigned to the task.


Like Iain9688 said, if you have more time to complete a project you can use it in better ways:

  • Find ways to reduce the cost of the project. For example, rush jobs always cost more.
  • Reduce risk to the project. For example, you can validate high-risk tasks by building proof-of-concepts.
  • Free up over-loaded critical resources.

However, if your real question is how do I apply a factor uniformly to the duration of all the tasks (as a purely mathematical exercise), here is a possible approach:

  1. Save your project in XML format.

  2. When you open this XML file in a text editor, you will see the durations appear as follows:


  3. You can write a script to read the string within the duration tags, parse it and replace it with twice the numerical value.

  4. When you reopen this modified XML file in MS Project, you should see the durations doubled.

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