A Gantt chart is a project planning tool that shows engineering tasks along a time axis. It helps teams see what work must be done, when it starts, how long it lasts, and when it should finish. Engineers use Gantt charts to coordinate people, materials, equipment, testing, and review steps.
This matters because complex projects often fail when timing, dependencies, or responsibilities are unclear.
In a Gantt chart, each task is drawn as a horizontal bar whose length represents its duration. Tasks can overlap when they can happen at the same time, but some tasks depend on earlier work being completed first. Milestones mark important events such as prototype completion, testing approval, or final review.
As the project runs, teams update percent complete and actual dates to compare planned progress with real progress.
Key Facts
- Task duration = finish date - start date
- A horizontal bar represents one task over a specific time interval.
- Dependencies show which tasks must be completed before other tasks can begin.
- Milestones are zero-duration markers for major checkpoints or decisions.
- Percent complete = completed work ÷ total planned work × 100%
- The critical path is the sequence of dependent tasks that determines the shortest possible project duration.
Vocabulary
- Gantt chart
- A Gantt chart is a schedule diagram that displays project tasks as bars across a timeline.
- Dependency
- A dependency is a relationship where one task must start or finish before another task can proceed.
- Milestone
- A milestone is an important project event or checkpoint with no planned duration.
- Critical path
- The critical path is the longest chain of dependent tasks that controls the minimum completion time of a project.
- Progress tracking
- Progress tracking is the process of comparing completed work and actual dates with the planned schedule.
Common Mistakes to Avoid
- Treating task bars as a simple checklist is wrong because the chart also shows timing, overlap, and order of work.
- Ignoring dependencies is wrong because starting a task before required inputs are ready can cause rework and delays.
- Making every task the same length is wrong because task duration should reflect estimated effort, resources, and technical difficulty.
- Failing to update progress is wrong because an outdated Gantt chart no longer helps the team predict delays or adjust the plan.
Practice Questions
- 1 A design task starts at the beginning of Week 2 and finishes at the end of Week 5. What is its duration in weeks?
- 2 An engineering project has Research for 2 weeks, Design for 3 weeks after Research, Prototype for 4 weeks after Design, and Testing for 2 weeks after Prototype. If no tasks overlap, what is the total project duration?
- 3 A team wants to begin manufacturing before testing is complete to save time. Explain one risk of this decision and how a Gantt chart could help the team evaluate it.