Gantt chart: A guide to optimising your project

"It is not too little time that we have, but it is too much time that we do not use." - Lucius Annaeus Seneca

As a project manager, you need to know how best to use the time available for the project. For this reason, time planning is carried out and an attempt is made to simply present time-relevant facts to the project participants through visualisation. In concrete terms, this means finding out how much time is needed for certain tasks or which time constraints have to be observed. Dependencies between different tasks should also be recognized and taken into account accordingly. The Gantt chart proves to be an extremely useful tool for getting the most out of time planning and visualisation, conveying more in one powerful image than a thousand words can express.
Five wooden blocks are stacked to form a staircase.


Basics of a Gantt chart and its components

The Gantt chart is a tabular bar chart named after the American mechanical engineer Henry Laurence Gantt (1861-1919). In project management it is used to plan the course of the project and to show the current project status. The Gantt chart makes it possible to list work steps such as activities or tasks as well as their results in one column per line and to display them as horizontal bars or milestones on a time axis. The length and position of the bars can be derived from general specifications and contracts or determined by intuitive estimates and assumptions.

Create a Gantt chart: step-by-step guide

For the successful scheduling, monitoring and control of a project with the help of a Gantt chart, it is crucial to refer back to the work packages defined in the Work Breakdown Structure and to the milestones defined in the phase plan or in the contracts, if applicable. Only on this basis can the project sequence be clearly presented in a Gantt chart.

Step 1: Define the task list

To create a Gantt chart, you must first define your task list, which contains all the tasks necessary to complete your project. You can either take these tasks directly from the Work Breakdown Structure as work packages or derive them from work packages. It is important to have a short description for each task to get a complete picture of the project.

Step 2: Determine the duration of each task

The next step is to determine the duration of each task. If the task is a work package, you can get the information directly from the work package description. For all other tasks, you need to make a realistic estimate to ensure that the chart is meaningful later. It is recommended to do the estimation in a team to ensure higher accuracy.

Step 3: Determine the dependencies

Once you have determined the duration of each task, you need to identify the dependencies between the tasks. Determine the order in which the tasks must be completed and highlight the tasks that are dependent on each other.

Step 4: Create a schedule

To continue creating the Gantt chart, draw a horizontal axis representing the time period of your project. The vertical axis contains the task list. For each task, draw a horizontal bar representing its duration. Each unit on the horizontal axis corresponds to a certain period of time, e.g. one week. For example, if a task takes 4 weeks, the bar should be 4 units long. Milestones marking important events in the project can be marked with a triangle in the week they are due.

Step 5: Add dependencies

You can use arrows to show the dependencies between tasks. If one task depends on another, simply draw an arrow line from the task to be done first to the second. This visually shows the relationship between the tasks and makes it clear which tasks need to be done first in order to proceed with others.

Step 6: Label the diagram

Give each task and the whole project a name. Also indicate the start and end date of the project. Do not forget to label the axes. Make sure the diagram is easy to read and understand and add colours to make it even clearer.

Step 7: Keep the chart up to date

Keep the Gantt chart up to date by reviewing it regularly and updating it as needed. Changes to tasks and dependencies need to be reflected in the chart to keep it meaningful and useful.

Common mistakes to avoid when creating and using Gantt charts include

"A fool with a tool is still a fool." The Gantt chart is an excellent tool, but for it to be fully effective it must be used correctly, and serious mistakes must be avoided.

Mistake number 1

The first major mistake often made by inexperienced project managers is to equate the Gantt chart with project management and start the project by creating the project plan. However, caution is needed here. The Gantt chart is only a project management tool, and it requires skilled groundwork to use it properly. If this is taken into account, the project can benefit from the support of the Gantt chart.

Mistake number 2

The second big mistake is that the Gantt chart is created virtually "off the cuff" without knowing exactly what it is about. In this respect, the following should be noted: The Gantt chart is based on work packages that have to be summarised in a Work Breakdown Structure (WBS). However, in order to be able to create a WBS, it must be possible to refer back to the project goal definition and the specification of the service to be provided. So if neither a goal formulation incl. specification nor a WBS with the relevant work packages is available, the Gantt chart will not work because the individual tasks and also their interdependencies cannot be understood correctly.

Mistake number 3

The third mistake is that project managers think they can work on the Gantt chart alone behind closed doors. This is not advisable. The recording of the work packages relevant to the project and their technical design, the so-called work package description, requires the cooperation of qualified team members in every project. As is so often the case in project work, teamwork is also important for the Gantt chart.

The Gantt chart in project planning and task tracking

If the project team has no experience with project management in general and the creation of a Gantt chart in particular, both the concept of project management and the Gantt chart as a tool need to be introduced and explained. Otherwise, a good-looking but useless plan will be created. This can neither properly penetrate the project nor provide a basis for project monitoring and control. Project planning needs to be updated regularly to keep track of tasks, and this updating naturally applies to the Gantt chart as well. If this necessary and possibly very time-consuming activity is not carried out consistently, one quickly has an outdated Gantt chart and then almost certainly has lost the overview of the project.

Gantt chart in combination with other project management areas

Milestone trend analysis

In addition to activities and tasks, the Gantt chart can also show outstanding events - milestones - in the course of the project. A milestone is an event of special significance in the course of a project, such as the completion of a phase or the completion of a subtask. Unlike activities, milestones are dimensionless and do not require time. The Gantt chart extended by milestones forms the basis for the milestone trend analysis (MTA), another important instrument of project management. With the MTA, the milestones are systematically observed and their shift in the course of the project is shown. From the shifting of milestones, conclusions can be drawn about schedule deviations and important corrective and supplementary adjustments can be made in the project.

Resource management

The Gantt chart can also be helpful for resource management. In the project, resources, i.e. personnel or material resources, are needed to realise work packages, for example. The task of resource management is to determine the required resources, to assign them to the individual activities in the project and to monitor and control their effective use. With the aim of being able to assign a suitable resource to each resource requirement, the resource plan provides an overview of the available or required resources. By assigning the required resources to operations, which in turn are linked to the time axis in the Gantt chart, the resource requirements can be identified, planned and controlled.

Risk analysis

In the Gantt chart, the critical path, i.e., the longest and thus time-determining chain of operations, can be shown directly in the flowchart. The critical resources are the bottleneck resources used on the critical path, which can be derived indirectly from the Gantt chart. The Gantt chart is also suitable for identifying project risks, which are then subjected to a concrete risk analysis and assessment as part of risk management.

When is the Gantt chart helpful?

Time and again, parts or the entire project must be completed by fixed deadlines, anytime and anywhere one can come under deadline pressure. This ranges from innovation projects (e.g. the development of a heat pump or the improvement of work processes) to investment projects (e.g. the construction of a football stadium or the design of a garden) to organisational projects (e.g. the relocation of production to a new production hall or the planning of the best friend's wedding). In all these projects the Gantt chart can find its application and everywhere it is also integrated into the project work by the project managers.

How a Gantt chart can be used in agile project management

In agile project management, as is well known, the responsibility for the work process lies with the agile team. While the team members, as a self-directing team, can intuitively derive the tasks to be worked on next from the Backlog, they can also use the Gantt chart to first estimate the time required for the individual tasks, then determine their sensible processing sequence and show what "usable" Increment can be expected at the end of the development cycle. In this way, a development cycle as part of agile project management can be usefully complemented by the Gantt chart as a tool of traditional project management.


The Gantt chart, which has been used as a tool in project management for more than 120 years, has lost none of its power despite many new trends. Whether for time and resource planning, monitoring and control or risk management of a project, when used properly it has proven to be an indispensable tool for many projects, then as now.

Gantt-Diagrammm - The IAPM logo.
Author: IAPM internal
Keywords: Project management, Gantt chart, visualisation

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