How to read a Gantt chart
Read down for the work and across for time. Each row is a task, and its bar runs from the day it starts to the day it finishes. Diamonds mark milestones, such as an approval or the launch. If someone has sent you a chart, find three things first: the end date, the tasks that are yours, and where today falls.
By the NeoGantt team · Updated
What each part of a Gantt chart means
Here’s a website project that runs for about ten weeks. Everything below refers back to it.
- Discovery
- Kickoff workshop
- Stakeholder interviews
- Sitemap & content plan
- Content & brand assets suppliedclient
- Discovery sign-off
- Design
- Wireframes
- Visual design
- Design review & feedbackclient
- Design approved
- Build
- Front-end development
- CMS setup & integrations
- Content entry
- Launch
- QA & browser testing
- User acceptance testingclient
- Go live 🚀
- Post-launch fixes
| What you see | What it means |
|---|---|
| Rows | One piece of work each, listed down the left roughly in the order they happen. |
| Time axis | The dates across the top. Here each column is a week (W1, W2…); other charts show days or months. |
| Bars | When a task starts (left end) and finishes (right end). Longer bar, longer task. |
| Groups | Bold rows such as Discovery or Design, with a thin bar spanning all the tasks beneath them. Read these first to get the shape of the project. |
| Milestones | Diamonds. A single date that matters: an approval, a handover, the launch. No length, because they’re moments rather than work. |
| Client tasks | Work that belongs to you rather than the team sending the chart, marked with a label, colour or logo. Here they’re outlined and tagged “client”. |
| Today line | A vertical line on live charts. Anything to its left should be done or under way. |
| Progress | A filled portion of a bar, a percentage or a tick. Not every chart tracks it. |
| Shaded strips | Weekends, public holidays or shutdowns. Durations usually skip these days, which is why a five-day task that crosses a weekend draws as a seven-day bar. |
Three things to find in the first minute
- When does it finish? Look at the last milestone, usually near the bottom right. In the example, that’s “Go live” in week 10, with a week of post-launch fixes after it.
- What do I need to do, and by when? Scan for your tasks. In the example the client supplies content and brand assets early on, reviews the design midway through and tests the site just before launch. These are the dates most likely to move the whole plan if they slip.
- What’s happening now? Find today’s date on the axis (or the today line) and read down. The bars it crosses are the work under way.
Then look at the diamonds in between. Each one is usually a point where you’re asked to approve something before the next phase starts. Our guide to Gantt chart milestones explains why they’re placed where they are.
What a Gantt chart doesn’t tell you
- A long bar isn’t necessarily a lot of work. Bars show elapsed time. “Content entry” might run for two weeks at an hour a day.
- Overlapping bars are normal. Tasks that run in parallel are planned that way, often by different people.
- Order doesn’t always mean dependency. Some charts draw arrows between tasks to show that one must finish before another starts. Many don’t, so if you want to know what’s waiting on what, ask.
- It’s a plan, not a promise. Dates move when scope changes or feedback runs late. A good plan shows where the risk is; it can’t remove it.
When the dates change
If you’ve been sent a live link, it always shows the current plan, so bookmark it rather than saving a copy. A PDF or screenshot is a snapshot of the day it was made; check the date on it before relying on it.
When something moves, you’re entitled to an explanation you can follow in one read: what changed, why, and what it does to the launch date. If you haven’t had one, ask. Most teams keep earlier versions of the plan and can show you what was agreed at kickoff.
Questions to ask about a Gantt chart you’ve been sent
- Which of these tasks are mine, and how much time will each need from us?
- What happens to the launch date if our feedback takes longer?
- Are public holidays and our own office closures accounted for?
- Where is the contingency, if there is any?
- How will you tell us when dates change?
None of these are awkward. A team that has planned the project properly will have answers ready, and the ones that haven’t are better found out in week one.
For the background, What is a Gantt chart? covers where they came from and what they’re good for. If what you’ve been sent is a single line of dates rather than rows of bars, Gantt chart vs timeline explains the difference. If you’re the one sending charts to clients, how to share a Gantt chart with clients is written for you.