The Gantt Chart was invented by Henry Laurence Gantt in the second decade of the 20th Century. Gantt was a mechanical engineer and needed a visual took for showing schedules and progress on the projects he was working on.

In the 1920s the Gantt chart gathered international acceptance as the way of recording project plans and was used on large constructions such as the Hoover Dam.

Nowadays the Gantt chart is commonplace amongst project managers with sophisticated project management tools such as Microsoft Project making Gantt chart creation available via information technology.

The Gantt chart itself displays tasks as bars across a timeline. Each bar indicates the planned start and finish time of task. In addition to the timing of tasks a Gantt chart will show the relationship a task has with other tasks in the project. These relationships are called dependencies.

A dependency might indicate that task cannot start until another has been completed or that two tasks must start or finish together. By creating accurate dependencies between tasks, a project manager is able to see how long a project will take to complete. The series of tasks that define the length of the project constitute what is called the Critical Path. If any tasks on the Critical Path are delayed, the project end date will be delayed.

Gantt charts can also indicate what resources have been assigned to tasks. These resources might include people, equipment or consumables. Using software such as Microsoft Project, a project manager can assess the availability of resources and also the cost of assigning a particular resource to a task.

Once a project plan has been finalised a Baseline is saved. This is a capture of the project's start and finish values, work values and cost values. This Baseline can then be used as a comparison with the actual start, finish, work and cost values as they are entered as the project progresses. A project manager can then monitor overspend and slippage.

If you are looking for a tool to help you create Gantt charts then the most commonly used software is Microsoft Project. MS Project is quite a complicated piece of software to learn and without proper instruction can appear to have a life of its own due to the complexity of its scheduling engine. For serious project management, however, it is probably the tool to go for. Without the resources to use Microsoft Project you may want to try Microsoft Excel. In Excel you can use a bar chart to emulate a Gantt chart, which although will be very basic in its functionality will also be very simple and easy to create. There are also some very clever Excel Gantt chart templates available online which will include functionality that you may not on your own be able to develop in an Excel spreadsheet.

Outside of the Microsoft family of software you will find options which include online Gantt charts.  The benefit of online Gantt charts is that they allow effective collaboration using cloud technology.