# How to stop people from submitting a form twice in Makeform

Duplicate prevention accepts only one completed response for each value in a selected field. It is free on every plan under **Settings** > **Access** > **Prevent duplicate submissions**.

**Is it free?** Yes. Duplicate prevention is free on every plan, but unavailable on forms with a Payment field.

## Steps

1. Make sure your form has an Email, Phone, or Short Text field that every respondent sees. Do not choose a field hidden from some respondents by logic.
2. Open your form and click the **Settings** icon in the top bar, then go to **Access**.
3. Turn on **Prevent duplicate submissions**.
4. In **Identify respondents by**, select the field you want to use for matching responses.
5. Click **Save Changes**.

Choose the field whose values you want to limit to one completed response each. The rule uses the value in that field to identify a repeat submission.

## How matching works

For email and short text values, matching ignores surrounding spaces and A–Z letter case. A change in capitalization or extra spaces around the value does not make it a different value for this check.

Phone values compare digits only. Phone formatting is not used to distinguish responses with the same digits.

Existing responses without a value in the selected field are kept and skipped. They are not deleted when you set up duplicate prevention.

## What respondents see

A respondent who has already submitted sees **Looks like you've already submitted this form**. This message relates to the value in the field selected under **Identify respondents by**.

:::callout{type="info"}
Duplicate prevention is unavailable for forms with a Payment field. There is no IP-address option.
:::

Makeform is a free AI form builder: describe what you want to collect and it builds the form for you, with unlimited forms and submissions on the free plan.

## FAQ

### Can I block duplicate responses by IP address?

No. There is no IP-address option. Select an Email, Phone, or Short Text field under **Identify respondents by** instead.

### Can I use this on a form that collects payments?

No. Duplicate prevention is unavailable on forms with a Payment field. This restriction applies even though duplicate prevention itself is free on every plan.

### Do uppercase letters count as a different email?

No. Email and short text matching ignores A–Z letter case and surrounding spaces. Phone matching compares digits only.

### What happens to older responses with no matching value?

Existing responses without a value are kept and skipped. Choose a field that every respondent sees when setting up the rule for completed responses.

## Related

- [Password protect a form](/help/guides/password-protect-a-form)
- [Close form rules](/help/features/close-form)
- [Email input](/help/features/email-input)
- [Form settings](/help/guides/form-settings)