Welcome to Common Logic and Calculations!

This page contains descriptions of advanced techniques and examples for you to use when building CommCare Forms.

Before diving into Logic and Calculations, we recommend you take a moment to read our article on Form Builder and review the Beginner Tutorial.


Display Conditions

Display conditions, sometimes also called skip logic,are used to determine when a particular question should be shown to a user. While you can use the Form Builder to make basic display conditions, it is also possible to create very complex expressions.

For more information please visit the Display Conditions page

Validation Conditions

Validation Conditions are used to require that a user enters a certain type of response. A simple example could be requiring that a date be in the future; simple expressions can be added using the Form Builder Expression Builder. However it is also possible to write very complex expressions which require a specific structure. A complex example would be requiring a code which is 5 digits long and starts with a letter.

You can also put a question-specific validation message which tells the user why their response did not meet the validation condition.


One of the most powerful features of CommCare is the ability to do calculations within a form by working with a special type of question called a hidden value. If you are just getting started using hidden values we recommend that you try going through the Hidden Value Calculations Tutorial.

Logic for Specific Question Types

Some question types are a bit more complex than others! These pages provide examples and explain how to work with some of these question types.

Advanced Form Design

This section has pages that you might want in order to build complex workflows or structures into your forms. Note that pages in this section may require knowledge of Case Management, a key feature of CommCare which is used to link forms together. 

Advanced Tools


On July 5, 2016, we released an update to the application builder that changes the way you reference form questions. To read more about the new references, see this overview