What is a Gantt chart?
A Gantt chart is a bar chart of a project schedule: tasks are listed down the left, time runs across the top, and each task is a horizontal bar from its start date to its end date. In one picture it shows what happens when, how long each piece of work takes and what overlaps, which is why it has been the standard way to draw a project plan for about a century.
By the NeoGantt team · Updated
What a Gantt chart looks like
Here is a six-week product launch drawn as a Gantt chart. Read down for the work and across for time. Phases are the bold rows, bars are tasks, diamonds are milestones.
- Research & positioning
- Market research
- Positioning & messaging
- Pricing strategy
- Positioning locked
- Launch assets
- Landing page
- Demo video
- Sales collateral
- Go to market
- Press & analyst briefings
- Beta customer program
- Launch day runbook
- Launch 🚀
- Post-launch review
In a few seconds you can see how long the launch takes, which work runs in parallel and where the key dates fall. The same tasks as a dated list would take a minute to read and still wouldn’t show you the overlaps.
The parts of a Gantt chart
| Element | What it shows |
|---|---|
| Task list | The work, one row per task, down the left-hand side. |
| Time scale | Dates across the top, in days, weeks or months. |
| Bars | Each task’s start, end and duration. Colour often shows the phase, team or owner. |
| Groups (phases) | Related tasks gathered under a heading, with a summary bar spanning them. |
| Milestones | Zero-length moments that matter, drawn as diamonds: approvals, handovers, launch. |
| Owners | Who is responsible for each task, including people outside the team. |
| Progress | How far through each task you are, often as a partly filled bar. |
| Today line | A vertical marker for the current date, so you can see what should be under way. |
| Dependencies | In some tools, arrows linking tasks so that when one moves, the tasks waiting on it move too. |
Not every chart has all of these. The first five are the core; the rest depend on how the chart is used. If you’re the person receiving a chart rather than making one, how to read a Gantt chart walks through each part from the reader’s side, and Gantt chart milestones goes deeper on the diamonds.
Why is it called a Gantt chart?
It’s named after Henry Laurence Gantt (1861–1919), an American engineer and management consultant who worked with Frederick Taylor in the scientific management movement. Gantt developed his charts in the 1910s. They looked different from today’s: many compared the work planned for each worker or machine with the work actually done, period by period, rather than listing a project’s tasks. They were used in American production during the First World War, and Wallace Clark’s 1922 book The Gantt Chart spread the method internationally.
Gantt probably wasn’t first. The Polish engineer Karol Adamiecki is usually credited with a similar diagram, which he called a harmonogram, in the 1890s. He published it more widely only in 1931, and in Polish, by which time Gantt’s name had stuck in the English-speaking world.
Two later changes shaped the chart as it’s used now. In the late 1950s, network methods such as the critical path method (CPM) and PERT added the idea of dependencies between tasks. From the 1980s, project software on personal computers made Gantt charts something anyone could produce, and the format became the default picture of a project schedule.
Types of Gantt chart
The format is the same everywhere; what varies is how much it tracks beyond dates.
- Simple (or presentation) Gantt charts show tasks, phases and milestones, and nothing else. Most client-facing plans are this kind.
- Progress Gantt charts add how far through each task you are, so you can compare where the work is with where the calendar says it should be.
- Baseline Gantt charts draw the original plan behind the current one, so slippage shows as the gap between two bars. Comparing plan with reality goes back to Henry Gantt’s own charts.
- Linked (scheduling) Gantt charts connect tasks with dependencies and calculate dates from them, including the critical path.
- Resource Gantt charts put people or equipment on the rows instead of tasks, to show who is booked when.
What is a Gantt chart used for?
Anything with a start, an end and several pieces of work in between. Common examples are website builds, marketing campaigns, product launches, events, software releases, construction and engineering schedules, and research projects and dissertations. Our Gantt chart templates cover the common ones with realistic phases and durations.
On most projects it does three jobs at once:
- Planning: laying out the work so the dates add up before anyone commits to them.
- Tracking: seeing what should be happening now and what has slipped.
- Communicating: giving clients, managers and suppliers one picture of the schedule. On client work this is usually the job that pays for the chart; see how to share a Gantt chart with clients.
Advantages and disadvantages of Gantt charts
| Advantages | Disadvantages |
|---|---|
| Readable in seconds, even by people who never open a project tool | Gets unwieldy past a few hundred rows; detail buries the plan |
| Shows overlaps and busy periods clearly | Shows time, not effort: a long bar may be light work, and workload isn’t visible |
| Makes deadlines, approvals and handoffs visible to everyone | Can look more certain than it is; dates are estimates |
| Works at any scale, from a two-week sprint to a year-long programme | Needs updating as work moves, or people stop trusting it |
| Gives teams and clients one shared picture of the schedule | A poor fit for continuous work with no end date, like a support queue |
One limitation belongs to the tool rather than the format. In a simple Gantt chart, moving one task doesn’t move the tasks that depend on it; you move them yourself. Dedicated scheduling tools such as Microsoft Project model dependencies, calculate the critical path (the chain of tasks that sets the end date) and reschedule automatically. On large projects with long chains of dependent work, such as construction or engineering, that’s essential, and those tools are the right choice.
When should you use a Gantt chart?
Use one when:
- the project has a fixed end date, or dates that other people depend on;
- several streams of work overlap and you need to see them together;
- people outside your team, such as clients, suppliers or approvers, own part of the work;
- you need to explain the schedule to someone who won’t read a task list.
It’s overkill for a handful of tasks, where a list with dates will do, and the wrong shape for ongoing work with no end, where a board works better. If you only need to show an audience a few key dates, a timeline is usually enough; Gantt chart vs timeline sets out the difference.
Are Gantt charts outdated?
No, though they were oversold for a while. In the era of heavy up-front planning, a detailed Gantt chart was often treated as the project itself, and agile software teams were right to stop planning every task months ahead. They now run day-to-day work on boards and backlogs.
So the board replaced the Gantt chart for one job, tracking a steady flow of tasks, and left the other job alone. The moment a project has a launch date, an event, a client approval or a contract deadline, someone still needs to see the work laid out against the calendar. That’s why Gantt views keep appearing in modern tools, including ones that started as task boards.
Gantt chart vs Kanban board
A Kanban board shows work by status (to do, doing, done); a Gantt chart shows work by date. Boards suit a steady flow of tasks where the question is “what should I pick up next?”. Gantt charts suit projects where the question is “will we finish by the date?”. Plenty of teams use a board for the week’s work and a Gantt chart for the plan above it.
How to make a Gantt chart
Paper, a spreadsheet or dedicated software all work, and the steps are the same in each: list the tasks, estimate durations in working days, put them in order, group them into phases and mark the milestones. How to make a Gantt chart walks through each step with a worked example. If you already live in spreadsheets, there are step-by-step methods for Excel and Google Sheets, and if you’d rather drag bars than edit formulas, NeoGantt’s Gantt chart maker runs in your browser.