Setting Up a Counter System for Vertical Hierarchy in Airtable

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6 - Interface Innovator
6 - Interface Innovator

I’m working on a project management system in Airtable, and I need to set up a counter system to assign unique numbers to tasks within a vertical hierarchy. The goal is to create a structured numbering system that reflects the task relationships and levels. Here are the details:

Project Structure:

I have a hierarchical structure with parent tasks ("Predecessors" field) and the associated subtasks ("Next task" field).
Each task can have multiple subtasks, forming a vertical hierarchy.


  • Assign a unique number to each task.
  • Ensure that the numbering system reflects the hierarchy (parent-child relationships).
  • Use a formula or automation to generate these numbers automatically.

Below is what I have tried:

I have tried to create 3 different fields as below:

1. tesst2:
Formula: IF(COUNTA(Predecessors) = 0, "1", "")
Explanation: This formula assigns “1” to tasks that have no predecessors (i.e., top-level tasks).

2. lookup test:
Formula: A lookup of the above field for the linked “Predecessors” field for the task.

3. test field:
Formula: {tesst2} + {lookup test}
Explanation: Combines the values from the previous two fields to generate the final task number.


I am unable to get any number greater than 2 using this method

1 Reply 1
6 - Interface Innovator
6 - Interface Innovator

This issue can likely be resolved with a combination of formulas, rollups, and possibly scripts or automations.

Could you provide a sample table or a more detailed description of how you envision the task numbers? Understanding the specific format you're aiming for (e.g., 1, 1.1, 1.1.1 for subtasks) will aid in crafting the right solution.

I recommend setting up a call with me so we can delve into the specifics of your Airtable setup and determine the best approach to implement this system using scripts/automations, formulas, and rollups.

- Juan, Code and No-Code Solutions Expert