# How baselines work

A baseline is a copy of the items a Gantt showed when the baseline was captured. For each item it keeps the type, the parent and every field value. After capture, only the name of a baseline can change. Later edits to the items never reach the copy, so it keeps showing the plan as it was.

## What a capture takes

A capture takes the items the view shows at that moment, after its filters. It holds up to 5,000 items. The new baseline is named with a number and the date of the capture.

A Gantt inside an item's page has no saved view of its own. Its baseline is recorded against that item, and the list marks it **Item**.

The baseline is shared. Everyone allowed to read baselines can compare against it. Which baseline a person compares against is that person's own choice, kept for this view in this browser. Two people on one view can compare against different baselines.

## How an item is judged

- The finish alone decides the color. An item that starts later but finishes on the same day is on plan.
- Distances are counted in calendar days, not working days.
- A red or green end on the ghost covers how far the finish moved.
- An item with no finish date, now or in the baseline, is shown as on plan.
- The comparison reads the Gantt's date fields as they are set now. Change those fields, and the ghosts move to the values the new fields had at capture. This works because a baseline keeps every field value.
- A parent's ghost covers what its items spanned at capture, under the parents they had then.

Pointing at a ghost also lists other changes: the fields that changed, a new parent and a new type.

## Added and removed items

An item the view shows now but the baseline does not hold is added. It is drawn blue, with a sparkle icon by its title.

An item the baseline holds but the view no longer shows is removed. It has no row. The **Baseline** page names it with one of two reasons: **deleted**, or **no longer in this view**, for example because a filter now hides it.

Under the list, the **Baseline** page counts what slipped, came in early, stayed on plan, was added and was removed. It names up to eight of the removed items.

## Which baselines are offered

The list offers the baselines that belong to this part of your organization:

- baselines from this view, and from the other views in its project, where the project is the nearest folder above the view in the sidebar;
- item baselines whose item this Gantt shows, or whose item the page belongs to.

Other baselines stay reachable through the search field above the list, which shows at most 20 matches. The baseline you compare against always stays in the list, marked with a check. Most of the time it sits in its usual group. A baseline the list would otherwise leave out, such as one found through the search, sits under **Comparing against** at the top instead.

An item baseline whose item was deleted shows **Root item deleted**. Nobody can compare against it until the item is restored from the trash.

## Who can capture, rename and delete

In the roles every organization starts with, **Administrator** and **Collaborator** can capture and compare. **Reader** can compare, but not capture. A custom role gets the same choices from its baseline permissions. See [Roles and permissions](../../roles-and-access/roles-and-permissions/).

Only the person who captured a baseline, or an Administrator, can rename or delete it. Deleting a baseline stops the comparison for everyone using it.

## Worked example

The dates are in March 2026. Build is captured from Monday 9 to Friday 13 March. Later, its finish moves to Wednesday 18 March.

1. Compare against the baseline. The Build bar turns red.
2. Under the bar, the gray ghost covers 9 to 13 March. A red end runs from 13 to 18 March.
3. Point at the ghost. It shows both date ranges and **finish +5 calendar days**.

## Next

- [Compare against a baseline](../../views/compare-against-a-baseline/)
- [Gantt view](../../views/gantt-view/)