Unable to create a formula field that has a rich text area field

## Limitation

Rich text area fields cannot be used in a formula. They can be used in validation rules and workflow rules.

Certain functions cannot be used on Rich Text Area.

## Workaround: Checking Empty Rich Text Area Fields

For example, while ISNULL could normally be used to check if a field is empty, a Rich Text Field Area field would require you to use LEN(Rich_Text_Area_field_Name) = 0 instead.

In the above example, if an image is inserted in the Rich Text Area, LEN will also not work unless a space is added after the image.

## Character and Size Limits

Salesforce supports up to 131,072 characters for each rich text area field and which takes size from 32 KB to 128 KB.

Where as Formula fields can contain up to 3,900 characters which can contain up to 4000 Bytes when saved and 5000 Bytes when compiled. Some functions, such as TEXT, DATEVALUE, DATETIMEVALUE, and DATE significantly increase the compile size.