Gantt Chart

What is a 'Gantt Chart'

A Gantt chart is a graphical depiction of a project schedule. A Gantt chart is a type of bar chart that shows the start and finish dates of several elements of a project that include resources, milestones, tasks and dependencies. Henry Gantt, an American mechanical engineer, designed the Gantt chart.


The Gantt chart is the most widely used chart in project management. These charts are useful in planning a project and defining the sequence of tasks that require completion. In most instances, the chart displays as a horizontal bar chart. Horizontal bars of different lengths represent the project timeline that includes task sequences, duration, and start and end dates for each task. The horizontal bar also shows how much of a task requires completion. The horizontal bar length is proportional to the time necessary for a task’s completion. In addition, the project tasks are visible on the vertical bar.

How It Works

A Gantt chart aids in scheduling, managing, and monitoring specific tasks and resources in a project. The chart shows the project timeline that includes scheduled and completed work over a period. The Gantt chart aids project managers in communicating project status or plans and helps ensure the project remains on track.

The chart identifies tasks that may be executed in parallel and identifies tasks that cannot be started or finished until other tasks are complete. The Gantt chart aids in detecting potential bottlenecks and helps to identify tasks that may have been excluded from the project timeline.

The chart depicts task slack time or additional time for completion of a task that should not delay the project, non-critical activities that may be delayed and critical activities that must executed on time. For example, if the project is installing new software on a server, the project tasks that require completion are conducting research, selecting a software, testing software and installing software. A milestone is selecting a software. These tasks appear as vertical bars on the chart. Each task takes 10 days to complete, and each task is dependent on the previous task. A critical activity is testing the software in the development and test environments. The task start and end dates, duration, and milestones appear as horizontal bars. The percentage complete for each task also displays on the horizontal bars. The project duration is 40 days. The project start date is July 23, and the project end date is Sept. 20, which is based on workdays.

When to Use

Projects of all sizes and types use Gantt charts. These charts are utilized in several industries and for a range of projects, such as building dams, bridges and highways, software development, and development of other goods and services. Project management tools, such as Microsoft Visio, Project, SharePoint or Excel, or specialized software, such as Gantto or Matchware, aid in designing Gantt charts.