What is a Gantt Chart?

Learn what Gantt charts are, their history, and how they can help you manage projects.

Marcin Gebicz Marcin Gebicz

A Gantt chart is a horizontal, timeline-based bar chart that represents a project plan in time. It was invented by Henry Gantt around 1910 and was heavily used throughout the 20th century for scheduling projects. Tasks listed to the left of the chart have their corresponding bars on the timeline and these visualize the workflow in a project. Start and end dates of tasks, milestones, dependencies between tasks, and assignees are classic components of Gantt charts. Modern software builds on the original concept: collapsible task structure, critical path, progress bars, resource management panels, and more can be found in Gantt chart software.

What is a Gantt chart used for?

Gantt charts are used by project managers and product managers to break down a project into manageable pieces of work, stay organized, and visualize dependencies between tasks.

Building and managing a comprehensive project

Project managers use Gantt charts to visualize the building blocks of a project and to break this single, huge project into smaller, more manageable tasks. The resulting small tasks are scheduled on the Gantt chart's timeline, along with dependencies between tasks, assignees, and milestones.

Staying organized

At the execution stage of large, organized and detailed projects, Gantt charts help visualize the process and progress. The tool aligns teams by keeping everyone focused on the same goals and working on a single timeline.

Determining logistics and task dependencies

Gantt charts can be employed to keep an eye on the logistics of a particular, even small, project. Task dependencies, which are visualized as colored arrows in most Gantt chart software, help ensure that a new task can only start once another task has been completed. If one task catches a delay, then some Gantt chart software may automatically reschedule the next task. This third use case addresses the needs of multi-team environments.

The benefits of using a Gantt chart

Gantt charts are useful for simplifying complex projects. The tool presents tons of data in an incredibly visual and aggregatable manner. The bar chart keeps tasks on track when there are multiple stakeholders and large, or numerous teams; or when the scope changes frequently. Another benefit of using the Gantt chart is maintaining a bird’s eye view on the whole project, especially on all milestones and deadlines. The Gantt chart is efficient as a first alert tool.

How to use a Gantt chart

Let's quickly go through a model Gantt chart workflow as it would be used by a waterfall or hybrid project manager.

  • Determine a project schedule: break projects into manageable chunks of work; schedule the resulting epics, stories, tasks, and sub-tasks in time (by setting start and end dates).
  • Establish roles, responsibilities and resources: ensure you've got enough resources for the amount of work and use resource management panes to avoid under-/over-allocation of resources.
  • Monitor project progress: use progress bars to monitor progress from sub-task to epic levels.
  • Identify milestones: milestones are moments of truth; accomplishments that teams should achieve on or ahead of schedule. They are optional but recommended.
  • Find and report problems: locate real, threatening problems using the Gantt chart and use critical path functionality to identify tasks that will affect the project's completion date.

Gantt chart examples

Gantt charts remain an important project management tool throughout various industries. At the end of the second decade of the 21st century, the Project Management Institute concluded that a mere 11% of organizations were fully Agile. In other words, 89% of organizations employ waterfall project management methodologies (usually at higher management level) in addition to the agile ones. This is called a hybrid approach. If you happen to think in 'dates and deadlines' then you're probably among those 89% that need timeline-based Gantt charts.

Two distinctively different Gantt charts apply to those who treat Jira as a project management tool (or PPM tool). The screenshots below come from a tool called BigPicture:

Project-specific chart

A screenshot of a project-specific Gantt chart | Atlassian Agile Coach

A project-specific Gantt chart is a detailed plan, using time tracking and progress bars for each sub-task, as well as arrows representing dependencies between tasks. Project-level Gantt charts tend to be used on the team level or within a department. This type uses milestones, critical paths, and baselines heavily, and these modern additions to the core bar chart collectively motivate the assigned team or department to deliver a product or a significant release on time. The collapsible work breakdown structure allows project managers to get a bird's eye view on the crucial stories of the project.

High-level, org chart

A screenshot of a high level org chart showing projects in the portfolio | Atlassian Agile Coach

Use the high-level, org chart to oversee a whole portfolio of projects. A bar on the org chart represents a project in the portfolio, rather than a task. The 'percent completed' for each project is a key metric here. You can also use statuses (new, in progress, completed), as well as baselines, to represent delays. A Chief Strategy Officer might use this variant of the chart for presentations delivered to the board of directors, CEO, or president.

Conclusion

The higher the level of management the more often you’ll see Gantt charts in action. Note, however, that many teams who proudly use agile roadmaps or boards use simplified Gantt charts, with iterations overlay added to the timeline. On the other hand, some advanced Gantt chart apps for Jira are capable of displaying sprints/iterations on top of their timelines. Both tools exploit the same concept, but Gantt chart apps for Jira are typically more feature-packed.

The Gantt chart is a universal tool. Teams can work in an agile, waterfall, or hybrid-style with modern Gantt chart software. Senior management, PMOs, and teams can virtually keep all of their work within a Gantt chart app and Jira. The tool is very scalable and equally applicable to the portfolio, large solution, program, and team levels, as per SAFe® guidelines.

Get your Gantt chart app from the Agile at Scale collection on the Marketplace.