What is Complaint Rate?
Quick Answer
The percentage of recipients who mark your email as spam — a critical deliverability metric.
Complaint rate = (spam complaints / delivered emails) × 100. Gmail requires complaint rate below 0.10% to avoid spam filtering, and below 0.30% to avoid temporary blocks. Yahoo/Outlook follow similar thresholds. Complaints spike when: you email unengaged lists, subject lines are misleading, the unsubscribe process is hard, or recipients don't remember subscribing. MisarMail monitors complaint rate in real time with alerts when approaching thresholds.
Related Terms
A system where mailbox providers forward spam complaints back to the sending email service.
Email DeliverabilityThe percentage of emails that reach the recipient's inbox rather than the spam folder or being bounced.
Sender ReputationA score assigned by mailbox providers based on your sending patterns, determining whether your emails reach the inbox.
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