> ## 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 where a formula applies

A formula's scope determines where it is used. Choose the broadest scope that matches the business rule.

## Default formula

A default formula is the fallback calculation for a property. Use it when the same business rule should apply across the model.

Example: Gross Profit is Revenue minus Cost of Goods Sold everywhere.

## Segmentation formula

A segmentation formula applies when the property is calculated using a particular dimension.

Example: calculate an allocation differently whenever Expense is broken down by Department.

A segmentation formula is about the grouping itself. It is not limited to one Department value.

## Segment formula

A segment formula applies to a specific dimension value or combination of values.

Examples:

* Department = Sales
* Region = West
* Department = Sales and Region = West

Use segment formulas for true exceptions. If every department needs the same expression, use a segmentation formula instead of creating one formula per department.

## Formula period

A formula can also be limited to a Formula period such as Actuals or Forecast. Formula periods use the Date dimension, so the formula must be scoped by Date.

## Combining scopes

Scopes can be combined. For example, a formula can apply only to Sales during Forecast.

The more specific formula is used where its full scope matches. Broader formulas remain available as fallbacks elsewhere.