Set per-task due dates using a Numbers column
TL;DR: Each task gets its own per-task offset (Numbers column) — when the subitem is created, its date becomes parent date + that offset. The #8 most-used Subitem Automation — used by 5% of all accounts.
What this does
Recipe: "When subitem is created, set its due date to match its parent due date + offset by this number column of days/weeks."
Each task gets its own unique offset stored in a Numbers column on the subitem. When the subitem is created, its date is set to the parent item's date plus that task's offset.
How it works:
- Add a Numbers column called "Offset" to your subitem board
- Each task has a different value (Design: 3, QA: 14, Launch: 21)
- Due date = Parent date + that task's offset value
When to use it
- Different tasks need different timing (Design +3 days, QA +14 days)
- Project templates with varied timelines
- You want to change offsets without editing the automation
- Using negative numbers for dates BEFORE the parent (event planning: −90 days)
If all tasks should get the same offset, use a simpler "set due date to parent + X days" recipe instead. This recipe is for varied per-task timing.
Before you start
- A Date column on the parent item (the reference date)
- A Date column on the subitem (the date to set)
- A clear list of which tasks need which offsets
Set it up (3 minutes)
Find the Subitem Automations App
1. Click either Integrate or Automate to find the Subitem Automations app.
2. Type Subitem Automations to search for the app.Click the Subitem - All automations app card.
Configure the Offset Automation
Info: The Subitem - All Automations library contains almost a hundred automations. Use the search function to quickly locate the recipe you need.
3. Search for "+ offset" to filter the automations list.
4. Click Use template on the first automation that reads: "When subitem is created, set its due date to match its parent item due date + offset by this number column of days/weeks/months".
5. Click the first due date placeholder to set the target column.
6. Select your Subitem Due Date column.
Info: You can also use a Timeline column instead of a Due Date column for either the parent or subitem. Choose whichever fits your workflow best.
7. Click the second due date placeholder to map the parent's date.
8. Select the parent item's Due Date column.
9. Click the number column placeholder to specify where the offset value lives.Select your subitem's Offset column.
10. Click days/weeks/months to define the timeframe unit, and select Days (or your preferred unit) from the dropdown.
11. Click the Create automation button to save and activate the rule.
Trigger Subitem Creation
To make things more streamlined and automated, you could also create another native
automation that generates subitems when your parent item's Status changes to something. And pre-fill the Offset value for each created subitem.
12. Click Create an automation to build a native recipe that creates subitems based on a status change.
13. Create an automation similar to what's shown below.
When mapping default values for the offset column, choose your numerical input based on how you want the due date calculated:
Negative Number (e.g.,
-10)subitem due date is scheduled before the parent item's due date.
Zero (
0)subitem due date matches the exact parent item's due date.
Positive Number (e.g.,
20)subitem due date is scheduled after the parent item's due date.
14. Enter your desired numerical offset in the Offset field.
15. Change the status of a parent item to trigger your new workflow.
Success: Your subitems will automatically generate with the right Offset value. And the Subitem Automation app will set their due dates accurately based on the parent item's due date and your specified offset values.
Q: Can I use a Timeline column instead of a Due Date column?
A: Yes, the subitem Automations app supports both Timeline and Due Date columns. You can use timelines for both the parent and subitem, or mix and match a timeline for one and a due date for the other.
Q: Will the subitem due dates adjust if I change the parent item's due date later?
A: There is a separate automation recipe available in the subitem Automations library designed specifically to adjust subitem due dates automatically when the parent item's due date is modified.
Common gotchas
- Every subitem must have an offset value. Empty Numbers cells = no date set.
- The offset column must be Numbers type — not Text. Recipes can't read text as a number.
- Use negative numbers for dates BEFORE the parent date (e.g. event prep: −90 days for venue booking).
- Date columns must exist on both parent and subitem. Names don't need to match — you map them in the automation.
- One automation handles all tasks. Unlike Set due dates by task name (from parent date) , you don't need a separate automation per task name.
- Pair with the on-change companion — use Sync subitem dates with the parent (per-task Numbers offset) to keep these dates in sync if the parent moves later.
Next up
Sync subitem dates with the parent (per-task Numbers offset) (the on-change companion — sync these dates when the parent moves)
Related
- Date & timeline automations (parent landing)
- Set due dates by task name (from parent date) (alternative — fixed offset per task name, no Numbers column)
- Date + offset — full reference
Still stuck?