Roll subitem dates up to the parent timeline
TL;DR: When subitem dates change, automatically update the parent item's Timeline column to span from the earliest start to the latest end across all subitems. The parent always reflects the actual project window. The #4 most-used Subitem Automation in the app — used by 8% of all accounts.
What this does
Recipe: "When subitems date/timeline changes, roll it up to its parent item timeline column."
The parent item's Timeline column reflects the actual range of all its subitems. Add a subitem with an earlier start? Parent timeline extends backward. Push a subitem deadline? Parent timeline extends forward.
When to use it
- Project status reporting — see the active window of every project at a glance
- Dashboards aggregating project timelines across many parent items
- You want the parent to reflect reality, not constrain it
- Roll-up reporting that needs accurate project bounds without manual updates
Before you start
- A Date or Timeline column on subitems
- A Timeline column on the parent item (must be Timeline type, not Date)
Set it up (1 minute)
Configure the Automation
1. Navigate to the Subitem Automations app's templates by clicking Integrate at the top of your board.
2. Enter "Subitem Automations" into the search bar.Select the Subitem - All automations app card from the search results.
3. Click the Search field inside and type "roll it up" to find the automation recipe.
4. Select the When subitem's date/timeline column changes , roll it up to its parent item timeline column automation recipe.
5. Click the underlined date/timeline link to configure the trigger.
6. Select your subitems' Date column or Timeline column (whichever you want to use).
7. Click the other underlined timeline column link to configure the target column on the parent item.
8. Select Item Timeline to map the subitem dates to the parent item.
9. Click Create automation to activate the rule.
Test the Roll-Up
10. Make a change on any of the subitems' date column or timeline column (whichever trigger you selected in the automation recipe)
11. Set a due date for a second subitem.
12. Observe the parent item's timeline column, which automatically updates to reflect the range between the earliest and latest subitem dates.
13. Click on another subitem's due date cell.
14. Select a date outside the current range to verify that the parent timeline dynamically extends its start or end date.
Common gotchas
- Parent column must be Timeline type, not a single Date. Rollups need a range.
- Empty subitems are ignored — they don't shrink the parent timeline.
- This is a derived value — don't manually edit the parent timeline; it'll get overwritten on the next subitem change.
- For a stricter "force exact bounds" behavior, see Keep parent dates aligned with subitems .
- For numbers (sum/avg/min/max/count), use Roll subitem numbers up to the parent instead — this recipe handles dates only.
Next up
Related
- Roll-ups (parent landing)
- Keep parent dates aligned with subitems (the strict bounds version)
- Date & timeline automations (the reverse — parent date drives subitems)
Still stuck?