Failure Rate is important in email marketing because it shows how many emails weren’t delivered. A high failure rate can harm your sender reputation, reduce deliverability, and signal poor list quality and directly impacting campaign success.
The formula for calculating email Failure Rate is:
For example, 10,000 emails are being attempted to be sent in which 150 emails failed to send due to technical or server issues. So the Failure Rate calculation is:
Here, the Failure Rate is 1.5%, which may be slightly high depending on industry standards. Ideally, failure rates should remain below 1% to ensure healthy email practices and maintain good deliverability.