Gantt chart milestones
A milestone is a single point in time on a Gantt chart, drawn as a diamond, that marks something being reached: an approval, a handover, a launch. It has no duration. Use milestones for the few dates that tell you whether the project is on track, usually one at the end of each phase.
By the NeoGantt team · Updated
Milestone, task or deliverable?
The three get mixed up constantly, and the chart reads badly when they are.
| Task | Deliverable | Milestone | |
|---|---|---|---|
| What it is | Work someone does | The thing the work produces | The moment something is reached |
| Duration | Days or weeks | None (it’s an output, not a period) | Zero: a single date |
| On the chart | A bar | Usually not drawn itself; its handover or approval is a milestone | A diamond |
| Example | Visual design | The homepage and template designs | Design approved |
So the task produces the deliverable, and the milestone records that the deliverable was accepted. If you can’t say what finishes on a milestone’s date, it’s probably a task in disguise.
What makes a good milestone
- It’s either reached or not. “Design approved” passes the test. “Design mostly done” doesn’t.
- Someone outside the team cares about it. A client, a sponsor, a supplier waiting to start. Internal steps nobody else tracks are just tasks.
- It’s named as an outcome. Past tense works well: “Contract signed”, “Venue confirmed”, “Site live”. “Design approval” could be a meeting; “Design approved” can only be one thing.
- It sits right after the work that earns it. Put it on the working day after the task it depends on finishes. A diamond floating in the middle of the next phase tells the reader nothing about what it’s waiting for.
- It changes what happens next. The best milestones are gates: the next phase starts only once they’re reached.
Milestone examples by project type
These are the milestones that come up again and again, in the order they usually fall. Each project type links to a template you can adapt. The templates keep to two or three milestones each, so add the ones your project needs from this list.
| Project | Typical milestones |
|---|---|
| Website project | Discovery signed off · Sitemap approved · Design approved · Content supplied · UAT passed · Site live |
| Website redesign | Audit findings agreed · Redirect map signed off · Design sign-off · Content migrated · Relaunch |
| Marketing campaign | Brief approved · Creative concept approved · Assets final · Campaign live · Results reported |
| Product launch | Launch date locked · Pricing confirmed · Sales enablement complete · Press embargo lifts · Product launched |
| Event | Venue booked · Speakers confirmed · Registration open · Run sheet final · Event day · Post-event survey closed |
| Software release | Scope frozen · Feature complete · Code freeze · Release candidate approved · Released |
| Research project or dissertation | Proposal approved · Ethics approval granted · Data collection complete · Draft submitted · Final submission |
| Client onboarding | Contract signed · Kickoff held · Access granted · Success plan agreed · First value delivered |
| Content calendar | Themes agreed · Calendar locked · First drafts approved · Campaign goes live · Monthly results reviewed |
How to use milestones for client approvals
On client work most milestones are approvals, and approvals are where schedules slip. Three habits keep them on time:
- Put a review task before every approval. A bar for “Client review: 3 working days”, owned by the client, followed by the “approved” milestone. The bar shows how long they have; the diamond shows when you need the answer.
- Agree what approval means. An email saying “approved” is clear. “Looks good, a few thoughts to follow” isn’t. Settle it at kickoff, including who can approve.
- Make the next phase start after it. If development starts before design is approved, the milestone is decoration. Everyone should be able to see that a late approval moves everything to its right.
For how to present these to clients and handle it when they slip, see how to share a Gantt chart with clients.
How many milestones should a Gantt chart have?
Usually one at the end of each phase, plus the final one. For a two- to three-month project that’s four to eight. A rough ceiling is one a week: beyond that, the diamonds stop standing out and people stop paying attention to them. If your chart has a milestone every few days, most of them are tasks, and the gates that count are lost among them.
Long projects can carry more, but look at them at the phase level: a year-long programme with a dozen milestones is fine if each marks the end of something substantial.
Common milestone mistakes
- Giving a milestone a duration. “Launch week” is a task. “Launched” is the milestone at the end of it.
- Milestones with no work before them. A deadline typed onto the chart with no tasks leading to it is wishful thinking, and everyone can tell.
- Hiding external dates. A board meeting, a trade show or a regulatory deadline that the project must hit belongs on the chart as a milestone, even though nobody on the team does anything on the day.
- Never moving them. When a milestone date becomes impossible, move it and say so. A chart showing a date everyone knows is wrong gets ignored.
What is a Gantt chart? covers the other parts of the chart, and how to make a Gantt chart shows where milestones fit in the process of building one. If you’re building the chart in a spreadsheet, the Excel guide shows two ways to fake the diamond.