Prevent duplicate submissions
Allow only one completed response per person, per email address or per answer.
Under Settings → Responses → Prevent duplicate submissions, choose:
| Option | How it works |
|---|---|
| Allow multiple submissions | Respondents can submit as many times as they like (the default). |
| One response per answer | Blocks a submission when a question’s answer matches an earlier response. Pick an Email, Phone, Short answer, Number or Link question as the Unique question. |
| One response per account | Each signed-in respondent can submit once. Requires Sign in to submit under Respondent identity. |
When someone tries again, they see “You’ve already submitted this form.” You can replace it with your own Duplicate message, or choose Use the default message.