How To Calculate Free Slack And Total Slack

In the field of project management, the notion of slack plays a crucial role. It is defined as the surplus time or resources that exceed the necessities for finishing a task. Slack can be categorized into two kinds: free slack and total slack. This article aims to explore the methods for calculating each of these measurements.

Free Slack

Free slack refers to the amount of time or resources available beyond what is required to complete a task without affecting the project’s completion date. To calculate free slack, we need to subtract the earliest start time from the latest finish time for each task in the project.

Example

Let’s take an example of a simple project with three tasks: A, B, and C. The earliest start time for task A is 0 days, and the latest finish time is 5 days. For task B, the earliest start time is 2 days, and the latest finish time is 7 days. For task C, the earliest start time is 4 days, and the latest finish time is 9 days.

To calculate free slack for each task, we need to subtract the earliest start time from the latest finish time:

• Free slack for task A = 5 – 0 = 5 days
• Free slack for task B = 7 – 2 = 5 days
• Free slack for task C = 9 – 4 = 5 days

Therefore, the free slack for each task in this project is 5 days.

Total Slack

Total slack refers to the amount of time or resources available beyond what is required to complete a task without affecting the project’s completion date. To calculate total slack, we need to subtract the earliest start time from the latest finish time for each task in the project.

Example

Let’s take an example of a simple project with three tasks: A, B, and C. The earliest start time for task A is 0 days, and the latest finish time is 5 days. For task B, the earliest start time is 2 days, and the latest finish time is 7 days. For task C, the earliest start time is 4 days, and the latest finish time is 9 days.

To calculate total slack for each task, we need to subtract the earliest start time from the latest finish time:

• Total slack for task A = 5 – 0 = 5 days
• Total slack for task B = 7 – 2 = 5 days
• Total slack for task C = 9 – 4 = 5 days

Therefore, the total slack for each task in this project is 5 days.

Conclusion

In conclusion, calculating free slack and total slack is an important aspect of project management. By understanding these metrics, we can better manage our resources and ensure that our projects are completed on time and within budget. We hope this article has helped you understand how to calculate free slack and total slack in your own projects.