How to make a Gantt Chart

If you never created a Gantt Chart you’re definitely interested in how to make a Gantt Chart. And to do this you either get a dedicated Gantt Chart software or create one in Excel. Both have advantages and disadvantages, which are explained in details in another article, and it’s up to you to decide which one is best for your projects.

Before you create your first Gantt Chart, you need to understand how Gantt Charts fit into the larger scheme of Project Management.
There are basically 3 important actions that need to be done before effectively creating the Gantt Chart:

  1. Create a list of all tasks
  2. Estimate the duration of each task and who’s responsible
  3. Think and decide which tasks are independent (or floating) and which depend on other ones

When you have all this information, you’ll be able to create a network diagram and/or draw the critical path. Being the longest sequence of tasks in a project that have to be completed to make sure you’re on time, it’s good practice to start drawing the Gantt Chart by putting in the critical path first.

If the project is less complex, it’s easier to identify the critical path and add it directly to the Gantt Chart. But if the project has many tasks, it’s much better to create a network diagram first and identify the critical path this way. A network diagram is basically a visual representation of all tasks, the duration and how they relate to eachother.

Network DiagramA network diagram for a web design project

In order to identify the critical path, you start from the left and calculate the longest duration of the dependent tasks; in the example above, the critical path is:

Research (3 days) > Written Plan (1 day)> Find collaborators (7 days) > Design (15 days) > Programming interface (30 days)

If you’ve estimated correctly, you now know the minimum required time or how long it will take to complete the project (56 working days in this scenario). Usually it will take longer to complete the project than your initial estimate, but we’ll talk in more detail about this in another article.

Now that you have all this information, you can add the tasks to the Gantt Chart software you’re using. It’s good practice to have the tasks in the critical path on top, because it will be much easier to follow and make adjustments in the Gantt view. Let’s have a look at the list of tasks:

List of tasks

As you can see, we have the tasks in the critical path on top, their due dates and people responsible for each task. The software will now automatically generate the Gantt chart and all that’s left to do is add the dependencies between tasks (if you use Excel, you’ll have to manually create the chart or use and modify an existing Gantt chart template).

How to make a Gantt Chart
Note: In order to keep the Gantt as simple as possible in our example, we’ve only added dependencies between tasks on the critical path.

The Gantt chart is now complete: on the left side is the list of all tasks and their start/end dates. On the right you can see the timeline, the 5 tasks that generate the critical path (along with task dependencies) and the 5 tasks that are not on the critical path.