What is difference between actual end date and planned end date expressed as percentage of planned duration?

The difference between the actual end date and the planned end date can be calculated by first determining the duration between these two dates. This difference is then expressed as a percentage of the planned duration by dividing the difference by the planned duration and multiplying by 100. For example, if the planned duration is 30 days and the actual end date is 5 days late, the percentage difference would be (5/30) * 100, which equals approximately 16.67%. This metric helps assess project performance and schedule adherence.