---
category: [Administration & Integrations, Administration & Integrations/Custom Integrations & Apps, Platform and Product Extensions, Platform and Product Extensions/Workday Extend, Platform and Product Extensions/Integration]
keyword: [Extend, Model Components, Extend Business Objects, MCBO, Model Component Business Objects, Business Objects, Model BO]
nav: wcp_docs
parent_url: /wcp_docs/
title: >- 
  Concept: Derived Fields
layout: subsection
---

Derived fields are fields on a Workday Extend business object that you derive from other fields in the business objects of your app. You can also use logical, arithmetic, comparison, and string-based operations in derived fields.

Extend uses Workday configurable security to secure derived fields, and generates a REST API for all derived fields in an Extend business object.

You can author derived fields in App Builder instead of recreating tenanted calculated fields when you develop your app. You can customize your reporting experience by creating calculated fields as needed.

You author derived fields as a sibling array in JSON to standard fields. Each derived field has an `id`, a `name`, a `label`, and a `type`.

When you author a derived field, you can use standard or other derived fields:

-   From the same Extend business object.
-   From any related Extend business object.


Each derived field must contain an expression that references at least 1 field in the business objects of your app. If you use a related business object in an expression, the related business object must be a target of the primary business object. Extend supports only a single-level hop between objects.

### Related Information

[Tutorial: Model Components: Derived Fields](https://wd5.myworkday.com/workday/learning/course/dfa49d237c9d016f69e98f56e0023c71?type=9882927d138b100019b928e75843018d)

[Reference: Derived Fields](/wcp_docs/syr1643821053546.html)

[Example: Add Derived Fields to Business Objects](/wcp_docs/yyj1643753159384.html)