Enter your optimistic, most likely, and pessimistic time estimates into the calculator to determine your expected project completion time using PERT methodology.
PERT Calculation Formula
The following formula is used to calculate the expected time for a project using PERT:
Expected Time = (Optimistic Time + 4 * Most Likely Time + Pessimistic Time) / 6
Variables:
- Expected Time is the weighted average time for project completion (days)
- Optimistic Time is the shortest possible time to complete the task (days)
- Most Likely Time is the most probable time to complete the task (days)
- Pessimistic Time is the longest possible time to complete the task (days)
To calculate the expected time, sum the optimistic time, four times the most likely time, and the pessimistic time, then divide the result by six.
What is PERT Calculation?
PERT (Program Evaluation and Review Technique) calculation refers to the process of estimating the expected time to complete a project. This technique helps project managers plan and coordinate tasks, making it easier to predict potential delays and prepare accordingly. Proper PERT calculation is crucial for project success as it helps in resource allocation, scheduling, and identifying potential risks.
How to Calculate Expected Time using PERT?
The following steps outline how to calculate the expected time using the PERT method:
- First, determine the optimistic, most likely, and pessimistic time estimates for the task.
- Next, use the formula from above: Expected Time = (Optimistic Time + 4 * Most Likely Time + Pessimistic Time) / 6.
- Plug in the values to calculate the expected time.
- Finally, compare the calculated expected time with the actual time to track project progress.
Example Problem:
Use the following variables as an example problem to test your knowledge:
Optimistic Time = 10 days
Most Likely Time = 15 days
Pessimistic Time = 20 days
FAQ
1. What is the optimistic time?
The optimistic time is the shortest time in which a task can be completed, assuming everything proceeds better than expected.
2. How is the most likely time different from the optimistic time?
The most likely time is the best estimate of the time required to complete a task, assuming normal circumstances, whereas the optimistic time assumes the best-case scenario.
3. What is the pessimistic time?
The pessimistic time is the longest time a task could take to complete, assuming everything goes wrong.
4. How often should I use the PERT calculator?
It’s helpful to use the PERT calculator at the planning stage of a project and whenever there is a significant change in the project’s scope or timeline.
5. Is the PERT calculator accurate?
The PERT calculator provides an estimate based on the inputs provided. For precise planning, it’s best to periodically review and adjust the estimates as the project progresses.