Custom Fields in Microsoft Project
Part five of a six-part series of blogs

Have you ever been frustrated when you can't find a suitable field for entering the data you want in a Microsoft Project plan? Well why not customise your own field and enter anything from simple text, to drop down lists, to complex calculations and even graphical indicators!

  1. Custom Fields in Microsoft Project
  2. Creating Drop Down Lists with Custom Fields
  3. Creating Calculated Custom Fields
  4. Using Functions in Custom Fields
  5. Custom Fields and Summary Tasks (this blog)
  6. Using Graphical Indicators in Custom Fields

This blog is part of a complete guide to customising Microsoft Project.  Wise Owl also run excellent MS Project classroom courses!

Posted by Andrew Gould on 01 August 2011

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Custom Fields and Summary Tasks

All of the custom fields that we've created so far in this series have been used with normal sub tasks - we haven't yet seen how a custom field works with summary tasks.  This article explains the various choices for controlling how custom fields behave with summary tasks.

Summary tasks and customs fields

This is what our set of custom fields looks like after we've inserted a summary task.

The Default Option

By default, any custom field that you've created and used with sub tasks won't do anything special when it comes to summary tasks.  This means that for both calculated and non-calculated custom fields you can type whatever you like next to a summary task.

Overtyping a calculated field

The Spend Variance field is a calculated custom field, but here we can happily type whatever we like next to the summary task.

The setting that allows this behaviour is shown in the diagram below: 

The default option for summary tasks with custom fields

The three options for how a custom field should behave in a summary task are shown at the bottom of this image - by default the option chosen will be None.

Rolling Up Custom Fields

For custom fields that contain numbers, a useful option is to Rollup their values into any summary tasks.  When you do this you can choose from a variety of aggregate calculations such as the total or average of the values in the subtasks.  The diagram below shows how you can do this:

Rolling up a custom field

Here we're choosing the Sum function for one of our custom fields. This means that any summary task will show us the total of all of its subtasks for this field.


The results of choosing this option for our example is shown below:

Rolling up two custom fields

We've chosen to Rollup the Sum of both the Task Budget and Spend Variance fields.

The result is that our two cost fields now show the correct answers, and we can't accidentally change these values by typing over them.

Using a Formula for Summary Tasks

The final option for controlling what custom fields do in summary tasks is to use a formula to calculate the result.  You can only do this for custom fields which already use a formula, such as the Spend Description field in our example.

Choosing to use a formula for custom fields

Choosing the Use formula option means that the same formula will be used to calculate the value for both sub tasks and summary tasks.


The end result is that our set of custom fields shows the correct values for all of the sub tasks and summary tasks in the project plan.

The full set of calculated values

The full set of calculated values.

What's Next 

In terms of the main functionality of our custom fields we've done everything we need to do.  However, as a final flourish, in the next article in this series we're going to look at how to assign graphical indicators to a custom field to turn a boring column of numbers into a fancy set of traffic lights. 

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