Calculate or update a field

Use Update or Calculate field to derive a value from a formula or condition rather than asking a respondent to enter it manually.

Example: derive an internal total

1. Add the source fields and give each a unique Name, such as quantity and unit_price.
2. Add a target field with a meaningful Name, such as calculated_total. Use a hidden field only if the value does not need to be displayed; hidden data is not secret.
3. Open Conditions > Update or Calculate field.
4. Select the target field and build the formula or condition from the intended source fields.
5. Save, then use Edit conditions to verify the rule references the correct internal names.
6. Preview with ordinary, boundary, and invalid source values. Confirm the computed target updates and does not create a circular dependency.

Expected result

The target value changes only from the documented inputs and formula. Validate that the calculated data is correct before using it in payments, notifications, exports, or workflows.

Action choices

• Copy: one source → one target; useful for mirroring a name or identifier.
• Copy multiple: several sources and literal text → one target; useful for a display label or address line.
• Calculate: evaluates a formula such as {quantity} * {unit_price} → one target.

Use braces around field names. Keep targets writable and distinct from source fields; do not create circular dependencies. Formula output is written to the target’s normal value and can be visible, hidden, exported, or used by later rules. Test evaluation order when one calculated field feeds another, and never rely on a client-side calculation as the sole authorization or price check.