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What is a PERT Chart? How to Draw a Detailed PERT Network Chart

PERT chart is an effective support tool for administrators in building a schedule for a large complex project. Using this chart will help businesses track the progress and development of a project.with Viindoo learn more about PERT network chart.

What is a PERT chart?

A PERT chart is a chart that shows the progress of a project, with the sequence of work to be done, the time and cost required to complete the project. In order to build project schedule management, the administrator needs to review the work that has been done before to determine the influencing factors, interdependencies as well as to anticipate the risks.

When using PERT charts in project management, administrators can track the progress of the project, determine the time and additional resources needed to ensure the project is completed on schedule. Take a look at this pert chart example, in which a production project consists of 7 tasks with the following length and sequence:


Time to perform (days)

Task sequence



Do it immediately without delay



Do it now without delay



Do it now without delay



Do it after it's done A



Do it after it's done A, B



Do it after it's done C



Do it after it's done F

In this case, the PERT chart of a project has the following form:

What is a PERT Chart? How to Draw a Detailed PERT Network Chart

An example of a PERT network chart

>>> See more: Project Management Dashboard - Why we need it?

When to apply a PERT network chart?

PERT network chart is often used in large-scale projects with multiple tasks and high complexity such as re-planning the human resource system of departments, changing salary structure and costs, etc. By simplifying and modeling jobs, employees easily grasp their tasks to perform. 

In addition, this chart is also applied in projects with large investment levels, combining many different departments and investors. The implementation based on the PERT network chart helps to simplify the process, support the work to be carried out faster and with higher efficiency. 

Pert charts are used in managing large, complex projects

Pert charts are used in managing large, complex projects

4 key elements of PERT charts

Events in PERT charts

The milestones in PERT charts mark the start and end dates of an activity in the plan, and it is considered an event. In PERT network charts, these events are usually represented by numbered circles. The event starts as the first circle being numbered 1 with only the arrows going out. The end event is the last circle with only arrows entering. Events in between have both in and out arrows.

What is a PERT Chart? How to Draw a Detailed PERT Network Chart

Events are one of the four key elements

PERT tasks

Tasks in PERT charts are operational tasks with scheduled execution time and personnel that, when completed, move to the next event. The work is represented as the seams between the circles. The length and time to complete the work will be expressed as the length of the line.

Standby time in PERT network

Standby time is the backup time in case work is delayed so as not to affect the overall schedule. This is the element of project risk management that should be marked on the supply curves of the work. In case the job is completed earlier than the reserve time, you can mark it with small dots on the arc.

What is a PERT Chart? How to Draw a Detailed PERT Network Chart

Reserve time is the time required in a project

Critical path of a PERT chart

PERT chart Critical path is a representation of the connection between tasks. This is also a way to help managers track the work progress chart. The longest critical path will be the length from the beginning to the end of the PERT chart. If any element on the critical path is delayed, it means that the work is behind schedule.

What is a PERT Chart? How to Draw a Detailed PERT Network Chart

Critical path is an important element of PERT chart

How to creat a PERT chart

After understanding the key elements in PERT chart, it will be more convenient to draw the chart. Here is a 5-step process to draw a PERT chart:

  • Step 1: List all the events and work to be done
  • Step 2: Prioritize the events
  • Step 3: Match the events events that depend on each other by graphs
  • Step 4: Calculate the specific completion time for each event
  • Step 5: Set up critical paths appropriately

Differences between charts Gantt and PERT

Another type of chart that is also commonly used for project management and systems is the Gantt chart. The common point between pert chart vs gantt chart is that they are both used to set up, track and monitor work in projects. However, these two types of charts have some major differences that you should know in order to choose the most suitable method.


Gantt chart



Column Graph

Network Chart


Henry L.Gantt

US Navy

Where to apply

Suitable for small projects, not too complicated nature

Suitable for large projects, high cost, complex nature

Distinctive features

Focus mainly on time to complete given tasks

Focus on events, work to form close relationships, not only time. 


Simple, easy to understand, easy to implement

Need to remember many principles, more difficult to apply. It is very important to visualize how the critical path is presented

>>>> Read more: Gantt Chart

Pert Chart FAQs

Visualization: PERT charts provide a visual representation of the project, making it easier to understand the workflow, dependencies, and critical tasks.

Task sequencing: The chart helps identify the order in which tasks need to be completed, ensuring efficient project progression.

Time management: PERT charts estimate the time required for each task, allowing project managers to allocate resources effectively and track project milestones.

Identifying critical path: The critical path represents the longest sequence of dependent tasks, determining the project's overall duration and highlighting tasks that cannot be delayed without delaying the entire project.

Risk assessment: PERT charts enable project managers to identify potential bottlenecks, resource constraints, and critical tasks that may impact project timelines.

Yes, PERT charts can handle uncertainties in task durations. PERT charts often use a three-point estimation technique, which considers optimistic, pessimistic, and most likely estimates for task durations. By using this technique, project managers can calculate expected durations and factor in uncertainties by considering a range of possible outcomes.

PERT charts are particularly useful for complex projects with many interdependent tasks. They are commonly used in construction, engineering, research and development, and large-scale projects. However, for smaller and less complex projects, simpler project management tools may be more suitable.

Complexity: Creating and maintaining PERT charts for large projects can be time-consuming and complex, requiring careful analysis and updates as the project progresses.

Accuracy of time estimates: PERT relies on accurate time estimates, which can be challenging to obtain, especially for unfamiliar or innovative tasks.

Lack of flexibility: PERT charts may not easily accommodate changes in project scope or unexpected events, requiring adjustments to task dependencies and time estimates.

Focus on time, not costs: While

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PERT chart is increasingly being used in businesses and organizations because of the benefits that this type of chart provides. Not only does it help improving work efficiency, but it also assists administrators in managing projects and track projects more easily. Hopefully this article of Viindoo has given readers an overview of this type of chart. 

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What is a PERT Chart? How to Draw a Detailed PERT Network Chart
Viindoo Technology Joint Stock Company, Monica Nguyen December 9, 2022

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