Gantt Chart

A Gantt chart is a horizontal bar chart that lays a project's tasks out against a timeline: each task is a bar positioned by its start and end date, so the whole schedule — what's happening when, what overlaps, and what depends on what — is visible at a glance.

Key components

• Task bars — one horizontal bar per task, positioned along a date axis by its start and end date, with bar length showing duration.
• Dependency arrows — lines connecting a task to the task(s) it can't start until finish, showing why the schedule is sequenced the way it is rather than just when things happen to fall.
• Critical path — the sequence of dependent tasks that determines the earliest possible finish date for the whole project, visibly distinguished (usually highlighted) from tasks with slack. See Critical Path for how to actually identify it.
• Milestones — zero-duration markers (usually a diamond, not a bar) for a significant date or deliverable, distinct from the ongoing tasks around them.

When it's useful vs. overkill

A Gantt chart earns its complexity on a project with real sequencing: multiple tasks that genuinely depend on each other, overlap in non-obvious ways, or share constrained resources, where seeing the whole timeline at once actually changes how the work gets planned.

It's overkill for loosely-ordered work — a list of tasks with no real dependencies between them is better tracked as a simple list or a Kanban board, where the useful signal is each item's current status, not its position on a calendar. Building a Gantt chart for that kind of work adds a maintenance burden (keeping dates and bars current) without adding information the team actually uses.

Common pitfalls

• Built once at kickoff, never updated — a Gantt chart is a live planning tool, not a one-time artifact; once real progress diverges from the original bars and nobody updates them, the chart actively misrepresents the schedule instead of informing it.
• Dependencies not actually drawn — a chart with bars laid out to look plausible but no dependency arrows looks precise while hiding the real critical path; anyone reading it can't tell which delays actually cascade and which don't.
• Too granular — breaking a project into so many small tasks that maintaining the chart (updating dozens of bars every week) takes more effort than the project itself needs defeats the point of using one.
• Critical path not distinguished — without a visibly highlighted critical path, a reader can't tell which delayed task actually pushes the finish date and which has slack to absorb a delay.
• Milestones drawn as tasks — giving a milestone a duration and a bar like an ordinary task blurs the distinction between "this is ongoing work" and "this is a specific date that matters."

Learn more

• Critical Path for identifying the sequence of dependent tasks that actually determines the project's finish date.
• Kanban for tracking status-based work that doesn't have real timeline dependencies.
• Project Charter for the document a Gantt chart's schedule usually supports rather than replaces.
• Meeting Agenda for using the chart's current state as the basis for a recurring status check-in.