> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cfo.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Choose between a Variable and a Dimension

> Decide whether a business concept should be modeled as a value or as a category that organizes and segments values.

Choose based on how people will use the field in the model.

## Use a Variable when

The field:

* Represents a financial value, performance measure, assumption, or operating input.
* Is added, averaged, counted, compared, or calculated
* Belongs in the values or line-item area of a financial table
* Is a result you want a formula to produce

Examples:

* Revenue
* Cash Balance
* Headcount
* Units Sold
* Average Salary
* Gross Margin

## Use a Dimension when

The field:

* Names a category
* Groups or filters other values
* Identifies where a value belongs
* Has items people use to break down a report

Examples:

* Department
* Legal Entity
* Region
* Product
* Customer
* Vendor
* Account
* Date

## Ask two questions

1. Is this the value I want to measure?
2. Or is this how I want to organize that value?

If it's the value, use a Variable. If it organizes the value, use a Dimension.

## Do not choose by data type alone

* Employee ID may contain numbers, but it identifies employees and is usually a Dimension.
* Gross Margin is a percentage, but it is a calculated value and is a Variable.
* Date is stored as a date, but it organizes values across time and is a Dimension.
* Headcount is a count, not a list of employees, so it is a Variable.

## A common ambiguous case: Account

A source Account or Account Code usually classifies transactions and is a Dimension. A modeled line item such as Revenue or Rent Expense is usually a Variable.

If several account values roll into one modeled result, Account is the organizing Dimension and the modeled result is the Variable.

## Related

* [What is a Variable?](/formulas/core-concepts/variables-and-dimensions/what-is-a-variable)
* [Segments, Dimensions, and cell addresses](/formulas/core-concepts/segments-and-segmentations)