Metrics > Spam Complaint Rate Spam Complaint Rate Definition: Percentage of email recipients who marked an email as spam.Formula: (Spam Complaints / Emails Delivered) × 100Why It Matters:A high spam complaint rate negatively impacts email deliverability and sender reputation. How to Improve: Avoid spammy subject lines Ensure unsubscribe links are visible Send emails only to opt-in subscribers Relevant Integrations: HubSpot Mailchimp Example Calculation:If 10,000 emails were sent and 50 people marked it as spam, then:Spam Complaint Rate = (50 / 10000)×100 = 0.5%