> For the complete documentation index, see [llms.txt](https://help.modelreef.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.modelreef.io/syntax/variables-syntax/subcategory-selection.md).

# Subcategory Selection

This article explains **Subcategory Selection** for variables in Model Reef.

You will learn:

* What subcategories are and when to use them.
* How they relate to main categories.
* How they appear in reports and dashboards.

Subcategories provide extra detail within a category without changing accounting behaviour.

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### What a subcategory is

A subcategory is a more granular label under a main category. For example:

* Category: `Revenue`
  * Subcategory: `Online`
  * Subcategory: `Retail`
  * Subcategory: `Wholesale`
* Category: `Opex - Marketing`
  * Subcategory: `Paid Ads`
  * Subcategory: `Events`
  * Subcategory: `Brand`

Subcategories let you break down totals into meaningful components.
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{% step %}

### Where to choose subcategories

You select subcategories in:

* The **Category Picker** in the Variable Editor, once a main category is chosen.
* The **import mapping** step, when line items are mapped to more granular reporting groups.
* The **Data Library**, for central control of how imported series are classified.

The available subcategories depend on the chosen category.
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{% step %}

### Impact on reports

Subcategories affect:

* How rows are grouped in detailed P\&L or cost reports.
* How drill downs from summary lines show underlying detail.
* How charts split a category into component series.

Totals at category level are simply the sum of all subcategories in that category.
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{% step %}

### Designing a subcategory scheme

Good subcategory design:

* Uses clear, non overlapping labels.
* Reflects how the business is managed (for example by channel, product or cost centre).
* Stays stable over time so that multi year comparisons make sense.

Avoid creating too many one off subcategories that only contain a single variable. Group related items where it helps interpretation.
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{% step %}

### Subcategories and imports

When mapping imported data:

* Use subcategories to align source lines with your reporting structure.
* Where source lines already have clear segmentation (for example product or region), preserve that structure in subcategories.

This makes imported models easier to read immediately after compilation.
{% endstep %}
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## Related articles

* [Category Selection](/syntax/variables-syntax/category-selection.md)
* [Allowed Operators](/syntax/formula-syntax/allowed-operators.md)
* [Archiving Models](/help/building-your-model/archiving-models.md)
* [Build a Live Actuals Model Using Xero](/how-tos/data-workflows-and-automation/build-a-live-actuals-model-using-xero.md)