Complaint rate is important in email marketing because it shows how many recipients mark your emails as spam. A high complaint rate damages your sender reputation, reduces deliverability, and can lead to your emails being blocked or blacklisted. Keeping it low ensures better inbox placement and protects your brand’s credibility.
The formula for calculating email Complaint Rate is:
For example, there are 12000 successfully delivered emails but 18 recipients marked the email as spam or complained. So the Complaint Rate calculation will be:
Your Complaint Rate is 0.15%. Since the industry benchmark is typically below 0.1%, this is slightly high and could affect your sender reputation if not addressed.
A 0.15% Complaint Rate is slightly above the ideal threshold (0.1%) and may negatively affect deliverability. If this is the case then you must improve email content and correct target audience can help reduce complaints.