PERT Chart vs. Gantt Chart: Choosing the Right Tool for Effective Project Management

PERT Chart vs. Gantt Chart: Choosing the Right Tool for Effective Project Management

By Maria Diab
Published: 7/12/23

Project managers across all industries and agile businesses frequently use PERT charts and Gantt charts to manage all aspects of a project, from estimating time frames to assigning tasks to team members and tracking all the moving parts.

Both PERT and Gantt charts are popular visualization tools that can help your company smoothly complete projects on time and on budget. But what is Gantt Chart vs PERT Chart? You need to know the difference.

In this article, we will explain the differences and similarities between both tools, as well as when to use them and how to decide which one is best for your specific project needs.

Understanding PERT Chart vs Gantt Chart

PERT charts and Gantt charts are similar in that they provide a graphical view of a project's tasks, schedule and timeline. But there are several crucial differences between these two types of project management charts. Let’s take a closer look.

What is a PERT Chart?

A PERT chart is a flowchart or network diagram that maps out project tasks using boxes, which are connected with arrows or lines that represent project dependencies and the various tasks that need to be completed.

This type of chart is used by project managers to highlight project milestones, track tasks and timelines, and identify any potential obstacles that may occur.

The use of a PERT chart allows you to estimate the minimum time required to complete a project, to analyze the distribution of work and the links between tasks, and to evaluate the associated risks. This is why this tool is particularly appreciated for planning a project before it starts.

What Is a Gantt Chart?

A Gantt chart is a project management tool that uses a bar chart laying out the start and finish dates of all project's elements such as tasks, milestones, planning, dependencies between tasks, and assignees. The left side outlines a list of tasks, while the right side has bars that create a timeline displaying the time allotted for each task.

Gantt charts, often referred to as roadmap tools, are the most widely used charts in project management. It is most often used when a project has already started.

What Are the Key Differences Between PERT Chart vs Gantt Chart?

Because PERT and Gantt charts are so different, project managers sometimes choose to use both tools in order to serve multiple purposes. Even though the PERT chart can be harder to interpret, especially for large-scale projects, it clearly illustrates task dependencies.

On the other hand, a Gantt chart doesn’t show clear dependencies but provides clear visibility of dates, goals and timelines.

We can summarize the differences between both systems like this:

PERT chart Gantt chart
Flowchart system, similar to a network diagram Linear bar chart
Can sometimes be confusing and complex, especially for large-scale projects Simpler and more straightforward
Best for internal project planning before a project starts Used once a project is underway and to communicate about the project’s progress to stakeholders
Focuses on:
  • The project milestones
  • The dependencies between tasks
Focuses on:
  • Each task and subtask of the project
  • The time required to complete a task
Main purpose:
  • Defining your project’s critical path
Main purpose:
  • Completing as many tasks as possible and on time for your project to succeed
Shows:
  • How long each task will take
  • How each task depends on others to succeed
Shows:
  • How long the project needs to take (but you need to estimate how much time you have for each task)
  • The timeline of each specific task to each task owner

How to Use PERT Chart vs Gantt Chart in Project Planning?

You can now see how both PERT and Gantt charts help simplify the project management process. It helps project managers increase efficiency and gain transparency as they can break down a project into smaller tasks and identify any constraints that may occur.

Although you can still use spreadsheets or traditional pen and paper, there are many dynamic Gantt chart and PERT chart software options available on the market today, like Wrike, TeamGantt, Freshbooks, Smartsheet, ClickUp, monday.com, Adobe Express…

These solutions provide a wide range of intuitive features to help you create your own charts and make the process smoother, more visual, user-friendly, and actionable.

Here are the different steps you need to take to develop a PERT chart and/or a Gantt chart.

How to develop a PERT chart

  • Step 1: List out your project milestones and tasks.
  • Step 2: Identify the sequence and order of those tasks. Be sure to point out any task dependencies.
  • Step 3: Determine the time criteria for your tasks: earliest start date, earliest finish date, and time to complete them.
  • Step 4: Create your PERT diagram by drawing it yourself or by generating it using a project management solution.
  • Step 5: Draw out your critical path - the most important steps necessary. This step will help you determine the minimum duration of the project.
  • Step 6: Update your diagram whenever you need to.

How to develop a Gantt chart

  • Step 1: Define the project outcome and time frame.
  • Step 2: Identify all essential project tasks: divide your project into subprojects, and then identify individual tasks for each subproject.
  • Step 3: Identify relationships between tasks. You can draw arrows between bars to set dependencies between different tasks.
  • Step 4: Add dates, assign tasks to team members, set milestones.
  • Step 5: Update completion of tasks as the project unfolds.

Advantages and Disadvantages of PERT Chart vs Gantt Chart

Advantages of PERT Chart

  • Great tool to visualize the project and display tasks
  • Great for identifying the critical path
  • Different timeline estimates help predict deadlines
  • Can be implemented before a project begins
  • Allows the manager to track required resources during any stage of the project
  • Clearly displays what each individual task on the project timeline needs, what prior tasks need to be completed before you can move on to the next, etc.
  • Helps with department coordination and communication during the project
  • Encourages you to look at all of the potential scenarios, making it easy to conduct what-if analysis.

Disadvantages of PERT Chart

  • May not be suited to all projects as it is very time-focussed and not very flexible
  • This is not the best tool if more than two projects need to share resources
  • Not as useful for monitoring projects that have already started
  • A PERT chart can look very complicated when managing complex projects
  • Modifying, maintaining or updating a PERT chart can be time-consuming as you’ll probably need to alter all of the subsequent project tasks on the project timeline.

Advantages of Gantt Chart

  • Very Flexible
  • Great transparency: easy visualization of the project timeline, all the individual tasks, subtasks and milestones
  • Easy time management: clear visibility of dates and time frames, by day, week, month, quarter and year
  • Easy to see which team members are responsible for which tasks, which helps project managers coordinate their teams
  • Easy to check the project status
  • Great visual tool to communicate to internal and external stakeholders about the project’s progress

Disadvantages of Gantt Chart

  • Gantt charts can be complex to create
  • Maintaining the chart can be time-consuming as it constantly needs to be monitored and updated
  • All tasks are not visible in a single view
  • Usually fails to represent some important factors such as the resources you need to accomplish the tasks, their level of difficulty, etc.

Which Chart is More Suitable for Your Project?

Well, it really depends on your project.

Project managers find PERT charts especially useful for planning projects where the duration of activities is uncertain. It helps them estimate task durations by assigning three time estimates per task: optimistic, most likely and pessimistic.

On the other hand, Gantt charts are particularly useful when managing a complex project. It helps project managers break it down into more manageable parts, easily visualize deadlines, and spot potential issues that may occur.

Choosing the Right Tool for Project Management

How to Choose Between PERT Chart and Gantt Chart?

You don’t need to choose between PERT charts and Gantt charts. The question is not which solution is best for your project, but rather when to use one or the other during the project.

Use a PERT chart when you need to:

  • Plan a project before it starts
  • Anticipate the amount of time you’ll need to complete the project
  • Identify the critical path to meet your deadlines
  • Visualize the task dependencies

Use a Gantt chart when you need to:

  • Anticipate the amount of time needed for each task
  • Clearly communicate task responsibilities
  • Communicate the project’s progress

How to Track Project Progress Using PERT Chart and Gantt Chart?

A PERT chart doesn’t really help you track a project’s progress, but it definitely helps you plan it and gives you an idea of how long the project should take.

On the other hand, a Gantt chart will help you track progress by giving you an instant overview of the entire project, its associated tasks in their order, and when these need to be finished.

What Are the Factors to Consider When Choosing a Project Management Tool?

PERT chart, Gantt chart, lists, Scrum Boards, Kanban Boards… There are now plenty of project management tools and software options available on the market to help you tackle projects, facilitate team collaboration, and gain both efficiency and productivity.

When choosing a project management tool, keep in mind the following key factors:

  • The specific needs of your team and the types of projects they work on
  • The likelihood of your team using it: Do they like this tool? How complex is it to use?
  • Which tasks does your team need the most help with?
  • Will this tool help your team communicate and collaborate?
  • Is your tool flexible and user-friendly enough to accommodate people with different skills, levels of seniority, aptitudes, etc.?
  • If you’re opting for a software solution, does it integrate with third-party tools?

PERT Chart vs Gantt Chart: Final Thoughts

No wonder why many project management solutions and software now provide both PERT and Gantt chart features. PERT and Gantt diagrams are very useful visualization tools that can become real assets for effective project planning and management, and help team members to work together more effectively, more efficiently and more accurately.

So ultimately, PERT chart vs Gantt chart: which should you choose? When comparing PERT chart vs Gantt chart, we can clearly see that both systems offer their own advantages and disadvantages at different stages of the project management process.

We would advise using a PERT chart to help you with the planning stage of your project. Once it has started, it is better to move on to a Gantt chart in order to keep an eye on progress and make sure deadlines are met, especially if you need to make changes along the way.

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