Gantt Chart vs Timeline: What's the Difference?
A timeline shows when things happen, in order, along a shared date axis. A Gantt chart shows the same information as one bar per task, with the task names listed down the left and each bar carrying its own duration, progress and dependencies. Every Gantt chart is a timeline. Not every timeline is a Gantt chart.
What a timeline shows
A timeline answers "what happened, and when". Events sit on a shared date axis, so what you read off it is sequence and overlap: which events came first, which ran at the same time, and how far apart they were. Events can share a row, which keeps a long chronology compact.
That suits history, research, legal chronologies, biographies and project retrospectives, where the events are the subject and there is no work left to schedule.
What a Gantt chart adds
A Gantt chart is a timeline arranged for planning work. Each task gets a row of its own, the names are listed down the left, and the bar beside each name shows when that task starts, how long it runs and how much of it is finished.
Giving every task its own row is also what makes room for the relationships between tasks, such as testing starting when development ends. That is the difference between a record of what happened and a plan for what is going to.
Side by side
| Timeline | Gantt chart | |
|---|---|---|
| Reads as | A record of when things happened | A plan for when work will happen |
| Layout | Events share rows on a date axis | One row per task, names listed on the left |
| Usual detail | Names, dates, notes, images | Durations, percent complete, dependencies |
| Suits | History, research, chronologies, storytelling | Project schedules, phased rollouts, hiring plans |
Which should you use?
Ask what the reader is meant to take away. If it is "here is the order these things happened in", a timeline is clearer, because events can share a row and the eye follows the sequence instead of a list of names. If it is "here is what happens next and how long it takes", use a Gantt chart, because one task per row is what makes individual durations comparable.
Longer projects often want both: a Gantt chart for the team doing the work, and a timeline of the same milestones for everyone else.
Building either one in Preceden
Preceden draws both from the same timeline, so you do not have to decide up front.
Add your events as usual and you have a timeline. To see those same events as a Gantt chart, click Appearance > Layers and check Use Gantt chart layout, or pick the Gantt Chart layout when you create a timeline. Creating Gantt Charts with Preceden covers the layer colors that make the result readable.
The details a Gantt chart needs are set on the event itself, under Add an Event to Your Timeline: choose a Percent Complete percentage to shade that much of the bar, check Dependent to start an event when another one ends so its dates move whenever that event does, and check the milestone setting to draw a date as a full-height vertical line instead of a bar.
What Preceden does not do is run the project. There is no way to assign a task to a person, balance workloads or calculate a critical path, so treat the Gantt chart layout as a way to communicate a schedule rather than to manage one.