Gantt Chart vs. PERT Chart vs. Network Diagram: What Are the Differences?


Project management can be boiled down to organization. Having the right information lined up and available to you is what leading a project is all about. But how can you make sure you’re getting the statistics you need to make the right decisions?

There are different types of diagrams that serve as ideal tools to help you plan, organize and control your project. They help project managers do their jobs better, by facilitating task coordination and stakeholder communications. Diagrams help you manage the triple constraint of time, cost and scope, which are the forces that exert their rule over every project. Often they are most useful for project scheduling, which is a process that can be greatly simplified with the help of diagrams.

Let’s compare three of the more popular examples of project management diagrams: Gantt Charts vs. PERT charts vs. network diagrams. What are they used for, what are the pros and cons, when in the project cycle are they used, which is best for what purpose? First, let’s define each, then compare the pros and cons.

What’s a Gantt Chart?

A Gantt chart is used to visually represent project schedules on a timeline. A typical online Gantt chart is broken up into two halves. Tasks are listed on the left side in a traditional spreadsheet fashion, but the timeline to the right offers a quick and easy way to understand the project schedule in its totality.

There are several ways to create a Gantt chart, such as using a Gantt chart template or even drawing one by hand. However, the best alternative is to use a Gantt chart maker. There’s a wide variety of choices available in the market, but they’re all not the same. Some Gantt chart makers are just an app with a limited featured set, while others come with robust project management features.

ProjectManager is more than just a mere Gantt chart maker, it’s a cloud-based project management software with project planning, scheduling and tracking features. Getting started is easy – you can start from scratch, or you can use one of five-built in, industry specific templates. Once you’re up and running, you can add tasks, set dependencies between those tasks, and calculate the exactly how long your project is estimated to take. If you’re looking for a Gantt chart that can fulfill all your project needs, try ProjectManager for free today.

What’s a PERT Chart?

PERT stands for Program Evaluation Review Technique, and refers to the method of using a graphic to plot the tasks that must be done to complete a project. It uses arrows to show the tasks needed to reach an event, which are symbolized by nodes. A node represents a completed project phase. They are used to help estimate the time it will take to complete tasks in a project.

PERT chart example
What Is a Network Diagram?

A network diagram is a schematic that shows all the tasks in a project, who is responsible for them and the flow of work that is necessary to complete them. In other words, they help visualize the project schedule. Like the PERT chart, it is also made up of arrows and nodes that show the course of tasks through the life cycle of a project. It can be used to track progress and scope once a project has been executed.

network diagram of a project

Comparing & Contrasting Gantt Charts, PERT Charts & Network Diagrams

It can be easy to confuse these three project management diagrams. They all work to help with schedules, and often do so in similar ways. But, for however much in common these three diagrams may have, there are distinct differences.

Let’s compare the Gantt chart, which is the workhorse of project management, to the PERT chart and network diagram, which are both network-style graphics. We’ll take a look at what they do and don’t do, so you know which is most viable to helping your project.

Gantt Chart vs. PERT

Both Gantt charts and PERT charts are visual tools that help organize tasks when building a project schedule. The obvious difference is that a PERT is a network diagram, while a Gantt is a bar chart.

PERT charts are great in that they clearly show you when a task is dependent. That is, if one task can’t start or end until another task has started or ended. Because it assists with calculating the critical path, you can also know what the early or late starts are for your tasks, which helps you predict how likely it is that you’ll get to end the project earlier. This means you can save time and make better decisions, managing data and what-if analysis.

A traditional Gantt chart typically doesn’t have this capacity.

Related: Free Project Scheduling Templates

On the negative side, it’s hard to scale a PERT chart. They can be a problem when working on larger projects, as it becomes overly complicated and difficult to quickly discern. If you want to print out the chart that, too, can be a problem because of their unruliness and size. The larger the project, the more complex the PERT chart and more difficult to read it. It’s also not a good tool to measure project progress, for which a Gantt has got it beat. Making a PERT chart is time-intensive.

Furthermore, a Gantt tends to focus on the time required to complete a task or its duration. The Gantt chart, at its most basic, is a simpler tool. Tasks are listed with a start and end date, and a line represents that span of time on the bar chart. They are especially easy to use with the help of a Gantt chart maker.

When it comes to Gantt chart vs. PERT, the decision is up to you, of course, and the scope of your project. Both have their pluses and limitations. But what about a network diagram?

Gantt Chart vs. Network Diagram

Like PERT charts, network diagrams are a flowchart that show the sequential workflow of project tasks, whereas a Gantt is a bar chart that shows the project schedule in a graphic representation.

Gantts tend to focus on tasks and time management while the project is ongoing. The timeline is easy to see, as it is clearly marked from its start date to end date. Resources can be added to the Gantt to help with allocation. Also, progress can be tracked, as well as status.

Network diagrams, on the other hand, are great for planning. They help to identify all the tasks you’ll need to complete your project. This includes finding those critical tasks and identifying float. This all works to make ordering materials and equipment easier, which assists in your financials.

However, network diagrams are not without their problems. One of the biggest is time. It takes a while to make one, and often time is the one constraint in a project you have the least amount of control over. So, you want to use your time as efficiently as possible. They can also bite into your bottom line. Network diagrams, like PERT charts, can be overly complicated as the project grows in size.

Online Gantt Charts from ProjectManager

Gantt chart, PERT chart or network diagram…. which to choose? While each has their purpose, Gantt charts have developed and matured as they moved from static paper to dynamic online platforms. ProjectManager is an award-winning cloud-based software that has taken Gantt charts to the next level.

Dependencies Made Easy

For one, our Gantt charts are not merely for scheduling timelines, though they do have a bar chart that lists all the project tasks and their durations. Using online Gantt charts allow you link to dependencies, which is one of the main draws of PERT charts and network diagrams. Just pull a task to the task that it is dependent on, and a dotted line appears between them. This lets you better manage your schedule while their executed, so teams aren’t blocked and you can avoid bottlenecks.

ProjectManager's Gantt chart, not the same as a PERT chart or a network diagram

Set Baselines & Track Progress

Network diagrams help managers calculate the critical path, but that’s a time-consuming equation. You can filter your Gantt charts by the critical path, and there it is, right on your timeline! In fact, the Gantt can be filtered in many ways, such as setting the baseline, so you can see the actual progress against your planned progress and keep the project on track.

ProjectManager's Gantt chart, showing the critical path of a project schedule

Automatic Updates & Easy Changes

A big complaint about Gantt charts is that they’re difficult to make. Then, when things change in a project, which they always do, you have to build another Gantt chart. Not with our tool. Editing is as simple as dragging and dropping the tasks to its new start or due date. Everything dependent on the task that changes is automatically updated and everyone associated with the task on the team is updated on that change, again automatically.

The Gantt is but one of multiple project views, including kanban boards, task lists and a calendar view. All of the views are seamlessly integrated with a larger suite of project management tools that manage resources, generate one-click reports, monitor progress at a high-level with real-time dashboards and so much more. PERT charts and network diagrams have a lot of catching up to do.

ProjectManageris an award-winning tool that organizes projects and teams, helping you better plan, monitor and report on projects. Online Gantt charts control tasks, kanban boards visualize workflow and dashboards track progress. All your project management needs in one tool. End the Gantt vs. PERT debate and try our online Gantt chart and suite of PM features today with this 30-day trial.

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