# Show or hide fields with conditional logic

> Build IF/THEN rules in the Logic tab so a question only appears when an earlier answer calls for it.

Conditional logic lets a form ask follow-up questions only when they're relevant. Open the **Logic** tab in the builder and write a rule — *IF* an answer matches, *THEN* show or hide a field. Respondents see fields appear and disappear as they type, without the page reloading.

## Build your first rule

1. In the builder, open the **Logic** tab.
2. Select **Add your first rule** (or **Add rule** if you already have one).
3. Under **IF**, select the **New condition** chip.
4. Pick the **Field** to test, an operator such as **Equals**, and the **Value** to compare against — for a choice field the value is a dropdown of that field's options.
5. Select **Done**.
6. Under **THEN**, select the **Show field** chip.
7. Choose the **Action** (**Show field** or **Hide field**) and the **Target field**, then select **Done**.

   On plans that include conditional notification routing, the same dropdown also offers **Send notification to**, which routes the notification email for matching responses to a different address instead of showing or hiding a field.
8. Select **Publish changes** to push the rule to your live form.

![A finished rule in the Logic tab: IF dietary restrictions equals Yes, THEN show the follow-up field](/docs-assets/building-forms/conditional-logic-1.png)

Each rule sits in its own card headed **Rule 1**, **Rule 2**, and so on, with a trash icon to remove it.

## The conditions you can test

The operators offered depend on the field you're testing, so you only ever see comparisons that make sense:

- **Equals** and **Does not equal** — on text-style fields, **Number**, **Currency**, **Date**, **Time**, and single-choice fields such as **Select** and **Radio**.
- **Contains** and **Does not contain** — on text-style fields such as **Short text**, **Long text**, **Email** and **Address**, and on multi-choice fields such as **Multi select** and **Checkbox list**. Multi-choice fields offer *only* these two plus the empty checks, because you're testing membership rather than an exact match.
- **Greater than** and **Less than** — on **Number**, **Currency** and **Date** fields.
- **Is empty** and **Is not empty** — on everything except yes/no fields, including ones with nothing else to compare like **File Upload** and **Signature**, which offer only these two.

Yes/no fields — **Checkbox**, **Toggle** and **Consent** — are the exception: they offer **Equals** only, since ticked and not-ticked already covers every case.

Testing an **Address** adds an **Attribute** dropdown, so you can match on the **Full address**, **Street address**, **City**, **State / Region**, **Postal / ZIP code**, or **Country** rather than the whole thing.

## More than one condition

Select **Add condition** to add another test to the same rule. A second condition reveals a **Match all / any of the following** switch: **all** means every condition has to be true, **any** means one is enough.

**Add action** works the same way — one rule can show or hide several fields at once.

## What respondents see

The rule runs in the browser as people fill the form in. Until the condition matches, the target field simply isn't on the page; the moment it does, the field slides in where it belongs.

![The public form with the follow-up field revealed after choosing Yes](/docs-assets/building-forms/conditional-logic-2.png)

The live preview in the builder behaves the same way, so you can test a rule by answering the preview on the left.

## If a hidden field is marked Required

It doesn't block the form. A field that a rule is currently hiding is skipped when the form is submitted, even when **Required Field** is switched on — so a "Yes/No" question can safely gate a required follow-up. Respondents who answer "No" never see the follow-up and can submit straight away.

## If you delete a field a rule points at

The rule stays behind and stops working. The **Logic** tab shows a **Logic warnings** panel — *A rule references "…", which no longer exists — it will never match* — and the rule displays the missing field's internal id instead of a name.

![The Logic warnings panel above a rule that references a deleted field](/docs-assets/building-forms/conditional-logic-3.png)

Maxforms also refuses to publish while that's true: selecting **Publish changes** returns *Can't publish yet — Fix the highlighted logic rules to publish.* Point the rule at a field that still exists, or remove the rule with its trash icon, then publish again.