A Gantt chart is a horizontal bar chart that shows the timeline of a project. It is one of the most important tools in project management because it gives an overview of the schedule of the project as well as the start and end dates for each phase and task in the project.
Gantt charts are often found in project management software like MS Project and can usually be exported to a jpg or PDF for inclusion in presentations or reports. It is possible to manually create a chart in programs like Powerpoint, Excel or Photoshop but they will be more difficult to edit than those created with proper Gantt chart software.
More about Gantt charts:
- each activity is assigned a name and number
- activities have start dates, end dates and durations
- activities can overlap
- the tasks or activities are listed one beneath each other down the left hand side of the chart
- the timeline stretches from the left (project start date) to the right and stops at the latest end date of any task in the project timeline
- tasks can be assigned predecessors. A predecessor is a specific task that must be completed in order for the next one to start. So if you are building a bicycle, a simple example would be that you need to put the wheels on before you can test ride it. Without the wheels it is impossible to ride the bike. So the task ‘test ride bike’ has a predecessor of ‘put on wheels’. It is not possible to start the task ‘test ride bike’ until its predecessor has been completed.
Gantt chart example
The example above shows a typical Gantt chart from MS Project for a project that spanned 7 months. It illustrates many of the important aspects of what this type of chart can tell you.
- phases and tasks can be broken down into hierarchies and sub tasks
- tasks can be expanded or closed which helps create global or more detailed views on the chart
- completed tasks are marked in the first column
- the assigned people or resources are shown
- important project milestones are marked as blue diamonds on the timeline
Gantt charts have their limitations including not being able to show real effort and slack (float) in the project, or illustrate more complex dependencies that can arise in projects with many moving parts.
They do however provide a good overview of the tasks that need to be completed, the timeline, and the resources involved, and are especially useful in the early phases of a project.