What is a Gantt chart?
A Gantt chart is the most widely used way to plan and communicate a project schedule. Tasks are listed down the left and drawn as bars across a calendar, so anyone can see what should be happening this week, what comes next and whether the project is on track. In quality and operations work, Gantt charts are used for validation and qualification projects, supplier approvals, CAPA implementation, audits, product transfers and improvement projects.
Elements of a Gantt chart
| Element | Shown as |
|---|---|
| Task | A bar from start to finish; the dark part is the % complete |
| Group / phase | A header row with a summary bar spanning its tasks |
| Dependency | An arrow from the end of one task to the start of the next |
| Milestone | A diamond on a single date |
| Today line | A dashed line showing where the project should be now |
Gantt chart example
The example plans the qualification of a new PCB supplier in four phases: planning, audit, qualification and close-out. The on-site audit can only start after the risk assessment, first article inspection and the quality agreement run in parallel after it, and the approved supplier list is updated only when the CAPA responses, the capability study and the quality agreement are all done. Planning tasks are complete, the risk assessment is 60% done, and the "Supplier approved" milestone falls at the end of November.
Tips for useful Gantt charts
- Keep tasks at the right level: one to ten days each, with a clear owner and deliverable.
- Link tasks so the chart updates itself when something slips.
- Find the tasks that drive the end date with the critical path method.
- Clarify roles for each task with a RACI matrix.
- Update weekly and use the chart in the project meeting; an outdated Gantt chart is worse than none.
How to use this Gantt Chart tool
- Name the project. Enter the project name and choose working days or calendar days.
- Add the tasks. Click + or "Add task" and enter the task name, group or phase, owner and duration.
- Link the tasks. Click a task and tick the tasks it starts after. Dependent tasks move automatically.
- Add milestones. Mark key events such as sign-offs or go-live as milestones (diamonds).
- Track progress. Update the % complete of each task. Unfinished tasks past their end date are flagged against today's date.
- Export. Export the Gantt chart to PDF or PNG for status meetings, or the task list to Excel.
Frequently asked questions
What is a Gantt chart?
A Gantt chart is a bar chart of a project schedule: each task is a horizontal bar on a calendar, from its start to its finish date. It shows at a glance what happens when, which tasks overlap, how far each task has progressed, and which tasks depend on others. It is named after Henry Gantt, who popularized it around 1910.
How do I make a Gantt chart?
List the tasks, estimate how many days each takes, decide which tasks must finish before others start, and give each task an owner. With "schedule from dependencies" on, the tool places every task after its predecessors automatically; you can also drag bars to set start dates.
What are dependencies in a Gantt chart?
A dependency links two tasks so one cannot start until the other finishes (finish-to-start, the most common type). If a predecessor slips, every dependent task moves too. The arrows on the chart show these links.
What is a milestone?
A milestone is a point in time with zero duration that marks an important event or decision, such as a sign-off, a delivery or a go-live. Milestones are drawn as diamonds and are useful checkpoints for reporting progress.
Should durations be in working days or calendar days?
Use working days for tasks done by your team during the working week; weekends are then skipped automatically. Use calendar days for things that run continuously, such as shipping or curing times. Switch the option at the top of the tool.
What is the difference between a Gantt chart and the critical path method?
A Gantt chart shows the schedule on a calendar and is the best way to communicate and track a plan. The critical path method calculates which tasks determine the end date and how much float the others have. Use both: CPM to analyse the plan, Gantt to run it.