# What is a Gantt chart? > **Gantt chart:** A Gantt chart is a bar chart that plots a project's tasks against a time axis: each task is a horizontal bar whose start, length and end show when it runs, and milestones appear as markers. - Source: https://ai-presentations.com/glossary/gantt-chart/ - Updated: 21 October 2026 - Language: English - German version: https://ai-presentations.com/de/glossar/gantt-diagramm/ Also called: Gantt diagram, Gantt schedule, project timeline, project schedule A **Gantt chart** is a bar chart that plots a project's tasks against a time axis. Each task is a horizontal bar: where it starts, how long it runs and where it ends show when the work happens. Milestones, such as a decision or a go-live, appear as markers on their dates. The chart is named after Henry Gantt, an American engineer and management consultant who developed and popularized it in the 1910s. ## Example The slide below shows a twelve-week engagement as three phases on a month axis, with two milestones drawn as diamonds on rows of their own. Phases that overlap run in parallel. *Three phases as bars on a month axis, and two milestones as diamonds. Example with fictional dates.* 5. Twelve weeks from kick-off to handover ## Parts of a Gantt chart | Part | What it shows | | ------------ | ---------------------------------------------------------------- | | Rows | One task, phase or workstream each | | Time axis | The calendar, in weeks or months, along the top | | Bars | When a task starts, how long it takes and when it ends | | Milestones | Points in time without duration: decisions, deliveries, go-lives | | Dependencies | Arrows that show which task must finish before another can start | | Today line | A marker for the current date, so progress is visible | ## From project plan to slide A planning tool holds every task, and a slide holds the story. For a slide, simplify: 1. **Show phases, not tasks.** Five to ten rows are readable. Put the full plan in the appendix. 2. **Pick one time scale and label it.** Weeks or months, with real dates or “Week 1 to 12”. Add the start date, because “Week 1” alone is ambiguous. 3. **Mark the moments that need the audience.** Decisions, approvals and handovers become milestones, and the slide says who is asked to act. 4. **Draw dependencies only where they matter.** A few arrows make the critical links visible. Many arrows make a tangle. 5. **Show where you are.** A today line or a status color tells readers what is done, what is running and what is next. 6. **Title the finding.** “Twelve weeks from kick-off to handover” gives the total duration, which is the point of most proposal timelines. ## Typical mistakes - **Too many rows.** A hundred tasks on one slide cannot be read. Group them and move the detail to the appendix. - **False precision.** Bars drawn to the day for an estimate promise more than you can keep. Use weeks or months. - **No milestones.** Without decision points, the chart shows busyness, not control. - **Colors without meaning.** Use color for the phase or the owner, and say which in a legend. - **A Gantt chart for a vision.** Themes without dates belong on a roadmap, not in a schedule. ## Related terms A [roadmap](https://ai-presentations.com/templates/roadmap/) shows themes over broad periods, while a Gantt chart shows dated work. The example comes from a [consulting proposal](https://ai-presentations.com/templates/consulting-proposal/), and the same slide fits a [project status report](https://ai-presentations.com/templates/project-status-report/), where [RAG status](https://ai-presentations.com/glossary/rag-status/) shows whether each bar is on course. ## Frequently asked questions ### Who invented the Gantt chart? It is named after Henry Gantt, an American engineer and management consultant who developed and popularized it in the 1910s. ### What is the difference between a Gantt chart and a roadmap? A Gantt chart shows tasks with exact start and end dates and often their dependencies. A roadmap shows themes or goals over broad periods such as quarters, without detailed dates. Use a Gantt chart to plan delivery and a roadmap to align on direction. ### How many tasks should a Gantt chart on a slide have? About five to ten rows. Show phases and milestones, not every task. Keep the detailed plan in a planning tool and refer to it in the appendix. ### What is a milestone in a Gantt chart? A milestone is a point in time with no duration, such as a decision, a delivery or a go-live. It is usually drawn as a diamond on the date it occurs. ## Related pages - [Roadmap](https://ai-presentations.com/templates/roadmap/): A roadmap presentation template with 8 slides: outcomes, now-next-later, release timeline, Gantt chart, capacity, dependencies and the decisions you need. - [Consulting proposal](https://ai-presentations.com/templates/consulting-proposal/): Propose the work in 8 slides: what you heard, the evidence, the approach in phases, the timeline, fixed fees per phase, the team and next steps. - [Project status report](https://ai-presentations.com/templates/project-status-report/): Report overall status, progress KPIs, schedule, workstreams, budget and risks on 8 slides, and ask sponsors for the decisions you need. With an example deck. - [Steering committee](https://ai-presentations.com/templates/steering-committee/): A steering committee presentation template with 8 slides: status headline, key figures, schedule, budget bridge, workstreams, risks and the decisions you need. - [RAG status](https://ai-presentations.com/glossary/rag-status/): RAG status is a traffic-light rating: red, amber or green. Definition, what each color means and how to show it on a status slide so it can be trusted. --- ai-presentations.com is published by Slaide (https://www.slaide.de), a sole proprietorship run by Nathalie Scholl in Heilbronn, Germany. [How this site is written, checked and corrected](https://ai-presentations.com/editorial-policy/).