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
- 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.
- Open your form and click the Settings icon in the top bar, then go to Access.
- Turn on Prevent duplicate submissions.
- In Identify respondents by, select the field you want to use for matching responses.
- 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.
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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.