Make a Milestone Timeline

A milestone is a point in time that marks a step forward: a contract signed, a product launched, a phase finished, a deadline met. It has a date but no duration. A milestone timeline lays those points out in order, usually next to the longer stretches of work or time that lead up to them.

Project managers use them to show where a plan stands without listing every task. They work just as well outside of projects, for the turning points in a company's history, a person's life, a business plan or a PhD.

Milestones vs tasks

A task takes time and has a start and an end date. A milestone happens on one date and usually marks the moment something is done or decided. "Build the website" is a task. "Website goes live" is a milestone.

If an item has no clear finish line, it is probably a task or a phase rather than a milestone.

How to pick your milestones

Start with the end. Put the final goal or deadline on the timeline first, then work back to the steps that have to happen before it.
Keep the ones that change something. A good milestone is a date people care about: when money arrives, when something ships, when a decision is made, when one phase hands over to the next.
Leave out the routine dates. Weekly meetings and minor check-ins belong in a calendar. A milestone timeline stays readable because it has only a few points on it.
Give each one a short, specific name. "Beta opens to 100 users" says more than "Beta".

Building a milestone timeline in Preceden

In Preceden every item on a timeline is an event, and any event can be made a milestone. Create a timeline, then add an event for each milestone:

Give the event a name and a Start Date, and leave the End Date empty.
Open More Options and check Make this event a milestone.
Click Add Event, or Update Event if you are changing an event that already exists.

Preceden draws a milestone as a faint vertical line at its start date, running the full height of the timeline, in the same color as the event. Its name and date stay beside it, so it can be read against everything else on the timeline.

Checking the box hides the End Date field, but it does not clear an end date the event already had. An event with an end date keeps its bar and gets the line on top of it. To get the line on its own, uncheck the box, clear the end date, then check it again.

Add the work around the milestones

A milestone timeline is most useful when it also shows what leads up to each date. Add the longer tasks or phases as ordinary events with both a start and an end date, so each one is drawn as a bar, and put them in layers by team or workstream. Each milestone's line then runs through every layer, which shows how each team's work lines up against it. Make a Swimlane Timeline covers that layout in more detail.

A few event settings help on a project plan:

Dependent, above the Start Date field, makes an event start when another one ends. If an earlier task slips, the dates after it move too. See Make an Event Start When Another Event Ends.
Percent Complete, under More Options, shades in how much of a task's bar is done.
Click Appearance, open Axis, and check Display a line on today's date to draw a red line at today. Milestones to its left should be behind you.

If you want one task per row with its name down the left, start from the Gantt Chart layout. Milestones work there too. See Creating Gantt Charts with Preceden.

Keep the milestones to a few

Every milestone draws a line across the whole timeline, so a lot of them turn into clutter and the important dates stop standing out. Preceden flags this for you: when more than 5 milestones are visible, Appearance > Recommendations suggests turning some back into ordinary events. 6 Tips for Creating Timelines with Preceden shows the same timeline with a few milestones and with too many.

The milestone setting is set in the event dialog. The Bulk Editor cannot set it, and it does not carry over when events are moved through a spreadsheet.

When the timeline is ready, export it as a PDF for a report or slide, or share a link so others can view it online. On a Pro plan you can invite collaborators to keep the milestones up to date with you.