Bounce rate
The percentage of sent emails that were rejected or could not be delivered, including permanent and temporary failures.
Email bounce rate is commonly calculated as bounced emails divided by sent emails, multiplied by 100. A hard bounce indicates a permanent problem, such as an invalid address. A soft bounce indicates a potentially temporary issue, such as a full mailbox or unavailable server.
If 20 of 1,000 sent emails bounce, the bounce rate is 2%. Review the failure reasons before deciding how to respond. Suppress invalid addresses and let the sending provider apply its retry policy for temporary failures.
A delivered email has been accepted by the receiving system; it may still land in spam. Bounce rate therefore measures delivery failures, not inbox placement. It is also different from website bounce rate, which describes visits rather than email delivery.
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